estimated by the companies themselves, because BTU per hour claims have become too unreliable and prone to exaggeration. In the past, the EPA did not require that test labs use actual efficiency numbers in heat output calculations, allowing test labs to use a range of efficiency estimates to make stoves look far more powerful that they actually are.
About 2,000 Quadra-Fire Mt. Vernon E2 pellet stoves and inserts are being recalled and repaired, due to high pressure that can lead to explosions that shatter the glass in the door. The company says the stove is safe if properly operated. The Consumer Product Safety Commission issued a voluntary recall on July 9, 2015. Problems were first reported to the company by consumers in the winter of 2015.
The problem is unique to this model and does not present a safety issue in other models sold by Quadrafire or any other manufacturer, according to pellet stove experts. If you own a Mt. Vernon, follow instructions in the voluntary recall notice and the company will repair the stove free of charge.
Some consumers and stove retailers contend that the stove was poorly designed and even if a stove is not operated properly, it should not build up pressures that can lead to explosions. At least 6 stoves have malfunctioned, leading to glass in the front door shattering, sometimes sending flying glass through rooms. No injuries have been reported. AGH believes the EPA should ask that this stove be re-certified since changes to it are substantial.
A number of discussions in independent chat rooms have raised the issues and include commentaries by affected consumers about how Quadra-Fire has responded.
The Alliance wrote to HHT asking for clarifications about what caused the malfunction and whether the stove would be 3rd party tested again for safety. We formally asked for information for our newsletter, which may have led to a less responsive reply, which is reproduced below.
———- Forwarded message ———-
From: Mathis, Kristen (HHT)
Date: Tue, Aug 4, 2015 at 11:34 AM
Subject: RE: questions about the Mt Vernon E2 for wood heat newsletter
1. Will HHT be sending this stove back to any 3rd party lab for safety testing?
When a modification is made to a Hearth & Home Technologies product, all necessary certification bodies are informed and the required testing is completed. Updates and notifications are published as necessary, and in accordance with the respective entities.
2. In your certification testing with OMNI, did any of the tests involve running the stove as the consumer might do it, instead of following the owner’s manual?
OMNI follows the testing protocols set forth in the test standard that the appliance is being certified to. The test standards follow ANSI protocol, and go through a revision process that allows for review and comment from interested parties to address future requirements and enhancements for performance and safety.
3. From your website and from talking to various HHT dealers, its confusing as to whether you consider this mainly a problem with incorrect operation by consumers, or whether its a flaw in the stove operating system. Your site says that the stoves in question will receive an enhanced control board “if necessary.” Are there some stoves that are not getting an enhanced control board or do all stoves in the recall get the enhanced control board?
HHT issued this recall proactively and in conjunction with the CPSC to reinforce our commitment to consumer safety. No injuries related to the Mt. Vernon E2 stove or insert have been reported. Issues of glass breakage are only related to Mt. Vernon E2 stoves and inserts when not maintained as outlined in the owner’s manual.
This recall affects an isolated set of units; if the unit is verified to be within the select group of recalled stoves or inserts, the control board should be replaced. HHT dealers have proactively contacted all consumers with affected stoves to have them repaired.
Lastly, you mention being unable to connect with someone at HHT. While I can’t speak to previous relationships, I do want to open the door for you to connect with me when you have questions moving forward. We always appreciate the opportunity to share factual information about our products and/or to share our passion and enthusiasm for the industry, and I can typically turn around responses in 2-3 business days.
Hearth Expert Sr. Communications Manager
This year there are at least half a dozen stoves on the market that have some automated feature that didn’t exist on the market a few years ago. Many of these features help the stove burn somewhat cleaner, and are aiming at a demographic looking for easier operation. It’s still too early to tell how well the automated features work, compared to what they claim to do.
Three major players in the US stove manufacturing community – Quadrafire, Travis and England Stove Works – now have automated systems to reduce start up and reloading emissions, which is one of the most important emissions issues that needs to be addressed. The Travis system uses electricity and is likely the most powerful of the three, and the other two don’t need electricity. The England Stove Works stove has integrated their innovation in a very affordably price stove.
The real promise of automation is not to get a hot stove to hit an ultra-low particulate matter number in a lab, but to improve real-world performance by seamlessly optimizing performance throughout the burn cycle, to reducing start-up emissions and reducing emissions from unseasoned wood. EPA certification testing does not attempt to test these attributes of a stove, so stove companies have not had much incentive to invest a lot of time, effort and money to design for that.
In the United Kingdom solid burning heating devices are not classified by their size, i.e. stove vs. boiler, but by whether they are automatic or manual. To achieve a rating to be used in more polluted areas, manually operated stoves must submit lab tests showing 5 burns for each output level because “manually controlled appliances show much higher variation between tests.” Automatic appliances only have to be tested 3 times at each output level.
The chart below shows a wide variety of technology that exists in both stoves and boilers in Europe, but only exists in boilers in the U.S., and much of it is imported from Europe. (Click here for PDF that includes this chart and some discussion of these issues.)
In November 2014, Brookhaven Lab will be testing automated stoves and prototypes at a stove design workshop to see how effective they are. Their designers aspire to be part of a real trend of cleaner, more automated residential wood heating. But can they do it at an affordable price point? And, are consumers ready for them? Here, we will look at stoves with automated features that are already on the market.
|A bi-metal coil acts as a heat-
sensitive thermostat which can partially
control the opening and closing of the damper.
1. The bi-metal coil. The oldest form of automation of steel wood stoves is the bi-metal coil which has been used on scores of stove models and is now mostly just used by a few catalytic stove makers, principally Blaze King and Vermont Castings. Some of the new automated features do something similar as the bi-metallic coil, but potentially do it much better. A bi-metal coil is simply a thermostat run by a metal coil that can close a damper down when its really hot, and open it up when its cooler. The stove’s air inlet can still be operated manually, but the bimetal coil will adjust the air inlet further. They tend to not work nearly as well on non-cat stoves, because the temperatures in a non-cat firebox can be more unpredictable, and if the coil shut down the air, or opened it too much, the stove would operate poorly – and critically – it adds far too much uncertainty in passing the EPA emissions certification test.
|The rotating trigger mechanism in the
Smartstove Collection by Englander
reduces air flow once the stove is hot.
2. The next three stoves – the England Smartstove, the Quadrafire and the Travis – all use different automated approaches to starting the fire quicker and with fewer emissions. After the start-up period, the stove operates like any other. The Smartstove by England Stove Works was displayed at the Wood Stove Decathlon on the National Mall in 2013, but it was still being certified by the EPA so it was not part of the competition. The stove has an “automatic air setback mechanism” which is a primary air control with a rotating trigger which controls the opening and closing of air vents. When the operator starts a fire, they gives the stove maximum air and sets the trigger. When the stove gets hot enough, the trigger releases and primary air is reduced, while still providing ample secondary air.
|Quadrafire’s Explorer 2 Start-Up air
control helps give the stove more
air in the first 25 minutes.
3. Another recent arrival on the market is Quadrafire’s Explorer II, which appears to provide similar automation. The website says “Automatic Combustion Control-provides the fire with air when it is most needed-leading to longer burns.” A marketing video says the operation is so easy that all you have to do is “load the wood, light the fire and walk away.” According to the installation manual, ACC is basically a timer which the operator must manually initiate with a control mechanism. Essentially, it opens the front air channel which allows air to enter for 25 minutes before closing. Once the front air channel is closed, manual controls are used to deliver preheated air to the top of the firebox to burn the rest of the unburned gases in the remaining three combustion zones.The Alliance confirmed with a company representative that no sensors are used or needed after the operator sets the timed control mechanism.
|The slider on the Cape Cod
adjusts the rate of burns.
4. Travis industries Hybrid-Fire technology™ developed an automated “Greenstart” which shoots 1,400 degree air into the firebox for 15 minutes to start your fire, or when you reload. The Greenstart can significantly reduce start-up emissions, and emissions during reloading on a low temperature bed of coals, by jumpstarting the start-up process and heating the wood up faster than it would with newspaper. After the first 15 minutes, the stove has no automated features, but some of the Travis stoves that use catalysts are among the cleanest in the industry. The Travis Cape Cod stove won second prize in the Wood Stove Decathlon.
5. The Nestor Martin’s Efel has an “automatic mode” that can keep the room at a desired temperature. Or in timer mode, it can adjust the room temperature at a pre-set time. The stoves uses a simple ambient air thermostat in a remote control device that you can operate from the couch or anywhere nearby. If you don’t use it in automatic mode, the remote control allows the user to adjust the intensity of the fire just as you would with a manual air control. One of the key things that distinguishes this Efel from truly automated stoves is that there are no sensors in the stove that can prevent the stove from smoldering or override an adjustment by the operator that would make the fire smolder.
|HWAM’s Autopilot technology uses
sensors, along with a bi-metal spring to
regulate combustion temperatures.
6. The final two stoves are more fully automated stoves and are on the market in Europe, but not in the US. Danish company HWAM, whose automation will be third-party tested and assessed at Brookhaven Lab in November, has integrated a new patented system-Autopilot. Along with the Austrian Rikatronic, described below, the Hwam is one of the most advanced and fully automated stoves in Europe. HWAM 3630 IHS features a control system that electronically measures combustion conditions through the use of a lambda oxygen sensor and a thermocouple. An onboard computer then allocates combustion air through three separate valves to help the consumer achieve the same results at home that are obtained in test labs under ideal conditions. According to the Danish Technological institute, HWAM stoves with this system are 17% more efficient and produce 40% more heat.
|Rikatronic has a microprocessor-controlled
motor and a flame temperature sensor
which drives the RLS air distribution system.
The light tells you the optimal time to reload.
By pressing the button, the stove knows
it has fresh wood to handle.
7. There are numerous versions of the Rikatronic wood heater system. The Fox II stove features manual and automatic control settings. In manual mode the air distribution can be controlled in each combustion phase-even in the event of a power outage. Automation in Rikatronic technology works with a microprocessor-controlled motor and flame temperature sensor which operates the RLS air distribution system. Airflow in each of the 5 combustion zones is effectively adjusted for efficient burn. A red light indicates the optimal time to reload the stove. You can set the room temperature you want and once the required room temperature is reached, you can activate the eco mode by pressing the Rikatronic³ button. This causes the air supply to be optimally controlled to maintain the fire for as long as possible, without smoldering, and to leave behind as little ash as possible. Power consumption is 2 – 4 watts.
The first five stoves described here represent American innovations that can partially reduce excessive wood smoke, while the last 2 stove from Europe represents a more holistic approach that can help reduce emission not just in the start up, but throughout the burn cycle. They are all still relatively new technologies and we are likely to see more companies improve upon them in coming years.
Updated on Nov. 24
Part of the Workshop rules was a requirement that teams had to publicly share their test results, which is a key part of the collaborative and educational process. During the Workshop, each team presented their test data to the 50 attendees who had the opportunity to discuss the results and give feedback to the team. Unlike EPA test, which starts when the stove is already hot, we used a warm start, capturing some start-up emissions, we used cordwood instead of crib wood and we used higher moisture content wood. Note: any gram per hour (g/h) references in the below test results are not comparable to g/h values from EPA test labs because we did not follow the Method 28 test protocol.
Team Presentations about their Stoves
Each team presented the concepts and technologies in the stoves. For a brief technical overview of all the stoves with contact info for the Teams, click here.
During the Workshop, there were a series of expert presentations and webinars about automation, traditional stove technology, public health implications, air quality, regulatory issues and other relevant topics.
1. Dr. Tom Butcher, Brookhaven National Lab, Review of the Automated Stove Test Protocol (powerpoint)
2. Webinar with the five teams, hosted by BTEC.
3. Glenn Miller, Fairbanks Air District, Technology Improvements vs. Behavior Modification (powerpoint)
4. Ellen Burkhard, NYSERDA, Renewable Heat New York (powerpoint)
5. Norbert Senf, MHA, Emission Testing of Masonry Heaters (powerpoint)
6. Gael Ulrich, Smoke Particle Formation Fundamental, (pdf)
7. Peter Cullen, Wohler SM 5000 (powerpoint)
8. Phil Swartzendruber, Puget Sound Wood Stove Retrofit Open Challenge (pdf)
Feedback Survey: Results of a 10 question feedback survey about the Workshop by teams, participants and organizers.
Photos: Day 1
|Ivana Sirovica, Jessica Peterson and Jeff Hallowell, from ClearStak Brookhaven National Laboratory.|
|Rebecca raking coal bed to prepare for the next load of fuel.|
|Thanks to John Pilger and Chimney Safety Institute of America and Olympia Chimney for donating pipe and installation!|
|Indigo Hotel in Riverhead NY – our base for the week|
|The Testo shows real time emissions, with top line showing particulate matter (PM)|
|Rebecca Trojanowski removes filters. The dark circle in foreground are the particulates on a filter from the test burn that will be weighed to determine grams per hour.|
|Even the kindling is carefully weighed so that each stove gets the same warm up rick.|
|Taylor Myers and Ryan
Fisher with the Mulciber,
the highest ranking stove.
|The Wittus team with the Twinfire.|
|The VcV, wired to monitor
temperature in key spots
|The ClearStak team with the
highest for emissions. It was a highly innovative entry, employing dual cyclones, a pre-heated, continuously engaged catalyst and a fabric filter. Its sensors and controller kept the oxygen rates incredibly steady, within half a percentage point. The technology could be integrated into a new stove, or added on to an existing stove. The designers did not try to optimize efficiency, which impacted their overall score.
|The Kleiss, ready for testing.|
The 12 member Organizing Committee oversaw developing protocols, testing and scoring and included representatives from Alliance for Green Heat, Aprovecho Research Lab, Brookhaven National Lab, Clarkson University, Hearth.com, Masonry Heater Association, Massachusetts Department of Energy Resources, Myren Labs, NYSERDA, US Forest Service and Washington Department of Ecology. The Committee is now considering options for a 2015 Stove Design Challenge.
A Comparison of Eligibility Requirements for Stoves Incentive Programs
October 31, 2014
* This efficiency level was not measured or enforced in any meaningful way.
** This program only allows upgrades from lower to higher efficiency using the EPA default numbers.
*** MD and ME allow for professional inspection in lieu of professional installation.
**** No efficiency minimum; higher efficiency stoves get higher rebate amounts.