In-floor/wood boiler compatibility
We are a new home in northern Wisconsin and are trying to deal with using a wood boiler to heat our in-floor system. Our HRV guy tells me that he doesn’t know of any other system like this and tried to tell our architect that we should switch to radiators, if we want to heat with wood. This is news to me. I’ve been away the past few days, and came home to an 84 degree home! Our ERV is a RenewAire and the woodboiler is a Royal. We are also having a huge creosote problem, but we are burning bone dry wood. Tomorrow, we are having the ERV motor replaced as it burned out after 2 months. Is it me or is there a way to make this work?
Replies
The problem you have with a setup like yours is getting consistent water temperature to your in- floor heat and only getting it there when you need it.
This is usually solved by zone valves, mixing valves, and somewhere to dump the excess hot water.
I like to dump it into a nice warm garage or shop or even an outside snowmelt system. If you have any of these, your heating guy should be able to set you up.
Thanks for the reply. We went out to watch the Packer game and came home to 84 degrees, again. There's something wrong somewhere. We have a heat dump to the garage that isn't working. The ERV guy said that temp has to be 180 or higher to divert to the garage. So, one more night with open windows in December. Is this such an uncommon system that the guys who instaled it can't even get it to work?!
Without seeing exactly what you have it's hard to give advice but....if you had a thermostat controlled zone valve in your house to cut off the flow of water to the house, I can't imagine how it could reach 84 degrees.
I don't understand why a regular three way mixing valve wouldn't work to control the water temperature entering your home system. The water doesn't need to be 180 for that to work.
Maybe it's time to have another look by a different heating contractor??
Is this an indoor or outdoor wood boiler? Creasote problems are a result of having to burn to cool a fire, Is your boiler lined with fire brick? If it is not the burn will not be hot enough to burn off the gasses and smoke particles that condense and cause creasote.
If you have really good insulation and an effiecent infloor system you may need a large storage tank for hot water. That way you can run the boiler hot with a small fire and store the heat produced.
The only problem with this set up is you have to rebuild your fire more often. Wood boilers are usually oversized by the "need" for longer burn times. This results in smoldering sokey fires and creasote.
I guess I don't understand the conection to the ERV burning up?
Garett
This is an indoor wood furnace lined with fire brick. There is a 51 gallon water tank. Don't know why the ERV motor burned up- will ask repair guy tomorrow. The thermostats are at 50 degrees and the 3 zones on the main floor are reading in the low 80's. The basement is a seperate zone and seems to be working.
Thought this would be an easy system to work. We've heated with wood in our previous home and want to so the same here.
Might be a dumb question but I've seen it before.
Are the stats the right ones for the zone valves?
We are a new home in northern Wisconsin and are trying to deal with using a wood boiler to heat our in-floor system. Our HRV guy tells me that he doesn't know of any other system like this and tried to tell our architect that we should switch to radiators, if we want to heat with wood. This is news to me. I've been away the past few days, and came home to an 84 degree home! Our ERV is a RenewAire and the woodboiler is a Royal. We are also having a huge creosote problem, but we are burning bone dry wood. Tomorrow, we are having the ERV motor replaced as it burned out after 2 months. Is it me or is there a way to make this work?
There's certainly a way to make it work - your HVAC guy and/or plumber ought to have a clue. We heat our new house exclusively with an outdoor boiler (Central Boiler) with a propane backup built right into the boiler. The house has five zones - one for hot water, and four for radiant floor heat. One loop heats the basement slab, one loop heats second-floor tiled bathrooms, one loop heats the master bedroom, and the last loop heats the remainder of the first floor (kitchen, living, dining, and 1-1/2 baths). The boiler PEX loop is connected to a large manifold with five zone drops, a heat exchanger and a circulator pump. It can best be pictured as links in a chain, where each link has its' own circulator pump, mixing valve and control system. At the moment, here in Vermont, we are heating the house ONLY with the basement slab. The thermostat, which is just a simple Honeywell classic t-stat, sits just outside the mech. room near the controls. It is set to 68 degrees. The basement is a bit on the warm side, maybe too warm, and the rest of the house gets to about 62-64 degrees and is comfortable in a t-shirt and jeans. Once in a while, on a sunny day with low demand and a full firebox, the boiler will steam up and boil, until demand kicks in or the fire dies down. The temperature in the house does not vary by more than two or three degrees, ever. On some days I will let the fire die, sometimes as much as 36-48 hours go by and the temperature in the house will drop to maybe 59-60 degrees. This is during the past two months when daytime temps are in the 40's and below 20 at night.
We are extremely happy with the system the way it is set up. I did a lot of research and did most of the system design myself. It's worth going outside and feeding that monster just to save myself $2500 a year in fuel costs. For that kind of money, I can pay for the entire system in six years. Plus I can justify buying a new chainsaw or two.
Oh, the creosote problem - with a wood boiler, you're gonna get creosote, period. The firebox temperature never really gets hot enough to burn it all off, even with bone-dry wood. You should see the inside of mine. It's sometimes a nasty black sticky mess, especially with a low fire and low demand. What I'll do is wait for a cold day and let the fire go out, load the box with dry pine and light it up, burn it all off with the door wide open. Burns it right out of the stack too - no worries about chimney fires at all since it's not in your house.
Talked with the HVAC guy to find out that he told our architect that the wood boiler wouldn't work very well with infloor heat. This was never conveyed to us. The challenge is to get a fire between 140 & 180, satisfy the in-floor needs, and not produce creosote. So far, we have not been successful, and I'm wondering if it's possible. There is creoste dripping out every possible spot and large puddles on the floor. Can this furnace be used without getting creoste all over? We want to heat with wood.
Indoor wood heat requires a different approach, not sure I have any ideas on that. You would probably need a consistently hot fire, a continuous draft, and a means of heat "storage".