Supplemental Heat with a Gas Fireplace? Has Anyone done this?

AJ3

Has anyone out there ever heard of someone using a gas fireplace as supplemental heat to radiant using a 2-stage thermostat? If so, I would be interested in some feedback.

I have a great room where the radiant (staple-up with plates) is falling short. We knew this would probably be the case with the initial calculations. I also will have a gas fireplace in this room as well, capable of somewhere between 6,000 to 45,000 BTUH, depending upon the setting. The fireplace can be controlled by any variety of millivolt thermostats. A remote control is also available that has a built in thermostat control. However, the remote, or separate thermostat in general, would work independent of the radiant thermostat, which may not allow the radiant to work that often.

My choice is between using the gas fireplace or adding about 10' of baseboard. Which would you do? Any input is appreciated.

Also, is a 2-stage thermostat the way to go or is there a better route?

Thank You

Larry_10

Neither...

Consider a panel ..or two . Panel rads are alot less of a mind bind altogether...*~/:)

AJ3

Are you saying that I should not take advantage of the heat from the gas fireplace for my supplemental? I hate to add additional elements to the room if I don't need to. Is there a reason why you think I should not use the gas fireplace?

I'm familiar with panel radiators and looked at them for this room but decided against it for the following reasons.

1. I have very little wall space in this room for mounting panel radiators. The only space I have is below the windows on one of the walls and they go down pretty far. I also have receptacles that are restricting me. I couldn't even get a 12" panel radiator below the windows. I know they make smaller panel radiators but at that point I'm approaching the same BTUH/FT output as baseboard.

2. I don't have them anywhere else in my house. I figured I would stick with baseboard since I already have plenty of it. I think a panel radiator will stick out too much in this room and I picture myself having to explain what it is everytime someone new enters the room.

If it wasn't for the first reason, I probably would have just used a panel radiator despite the second.

Ted_9

AJ, do you know how much supplemental is required?

Calcs were done, so you have a radiant heatloss.

I would say stay with the fireplace. I dont know what to do about the 2 stage t-stat. Maybe with a 24v transformer and a isolation cube relay, you can use the Tekmar 2 stage t-stat. The milli volt connected to one side of the relay and the 24v to the other side with the t-stat.

PATRIOT HEATING & COOLING, INC.

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AJ3

Heat Loss Info

Ted,

I appreciate the response.

Per the calcs, I need about 4800 BTUH but I was going to go a little extra to 6000 BTUH, which is the minimum output of the gas fireplace. The model I'm looking at can go up to at least 30,000 BTUH.

I did have a question about millivolt systems. Is the actual operating voltage 750mV? My understanding is that the gas fireplace generates the 750mV and the thermostat simply switches it. Is this correct?

If the thermostat is simply dry switching a voltage, 24V or 750mV, then why do they have thermostats that are specifically rated for millivolt applications? Couldn't any 24V thermostat with a relay switch through 750mV? Is it simply a matter of having a specific electrical rating for it?

Is there a 2-stage thermostat on the market that can handle both 24V and millivolt?

Ted_9

Like I said, I havent done this. I would call Tekmar and see what recommend, if you are going with their stat.

PATRIOT HEATING & COOLING, INC.

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Weezbo

*~/:) well, with the dedicated space for a fireplace....

have you considered making a hearth with hydronic radiant appointments? perhaps a Virtual fire place might fly ....

jeff_51

That,s done all the time out here

The fireplace stores out here do a very good job of selling gas fireplaces for supplemental heat. Is used alot in additons where adding to the forced air system is impractical where three season porches are upgraded to four season rooms etc. They aren't the most efficient, but with the controlled blowers etc, you might as well get some use out of it instead of letting all the heat get wasted up the flue. Alot of direct vent models are available so flue is usually not a problem. Besides, you and moma can get cozy and that ain't bad

Steve Miller

KISS

I wouldn't get too fancy with it. Just set the gas inserts Tstat a degree higher that what the radiant will max out at. If you haven't brought the insert yet, see if they have one with a 24v gas valve or convert the millivolt valve and limits to 24v and and get a 24v 2 stage thermostat.

Mitch_4

I have one as supplemental in my rec room

and it makes for great ambiance too. light the fireplace, play pool, watch tv.. whatever. The bonus is that it requires no electricity except for the circ fan (which is optional) and it can be run without. So when I loose electricity (up to 48 hrs sometimes) I still have a hot spot in the house where we congregate and keep warm.

I have forced air, not radiant, and when I finished the basement, I didn't want to heat it 100% of the time, so I ran a couple ducts to keep the chill out, and the fire place does the rest!.

Good luck./

Mitch

Jack_21

Rinnai 1004 10,500-38,000BTU)DV wall furnace

81% efficinency, Modulating gas valve and blower. 3" hole for the vent. Quiet and cool to the touch. If yu can use the 556WTA (8,200-21,500 BTU, 84%AFUE) I would do so. It has a set-back t-stat built in. Do not use a two stage stat the Rinnai has its own and you can just set its temp to co-ordinate the two. Very high quality and high reliablilty. Gas fireplaces are not particularly efficient and will not begin to heat as well as the Rinnai.

Bob Harper

gas fireplaces as supplemental heaters

As a factory rep. for the largest Fp mfr., I can advise you on this. First of all, I ask that you visit www.fireplaces.com to search the various models and get info. What you are looking for is a heater rated appliance listed to ANSI Z21.88 and AFUE rated. We have some models that approximate the AFUE of the Rinnai but unlike a wall heater, ours look like a real fireplace with realistic firebrick, glowing logs and embers, adjustable flame heights, and blowers that can be controlled by various remotes and smart wallswitches. I recommend an IPI ignition(Intellifire system) with the cabin kit so if you lose power, it will automatically backup from two D cell batteries(3 volts DC). I also recommend the WSK-MLT which is a multi-function wall switch that functions as a T'stat, flame height adjustment, blower control, and has a convenient digital room thermometer all of which can be located on the other side of the room unlike most millivolt T'stats. The key here is supplemental heat--not primary heat.

As for modifications, my answer applies not just to our appliances but all listed appliances: If you tamper with an appliance and modify it from its original listed condition such as changing ignition sytems in a manner not recognized by the mfr. you void the warranty and assume all liability! Don't do it!!!


As for the 750 millivolt systems, that means the valve is rated at 750. However, most systems are more happy at a resting 450-550 mv and under load at ~200-250mv. If you do choose a mv system, you'll need to use a mv T'stat which is designed to operate at the much lower power levels. This is why many ordinary light switches struggle with mv systems--they are designed for 110vac and not a fraction of one volt dc.

Jack_21

yes, the Rinnai can be the sole source of heat

And if you install it, you may find that it becomes that. Many have. 81% efficiency, Modulating gas valve and blower. 3" hole for the vent. Quiet and cool to the touch. If you can use the 556WTA (8,200-21,500 BTU, 84%AFUE) I would do so. It has a set-back t-stat built in. Do not use a two stage stat the Rinnai has its own and you can just set its temp to co-ordinate the two. Very high quality and high reliablilty. Gas fireplaces are not particularly efficient and will not begin to heat as well as the Rinnai.

Should you choose a fireplace, you may want to check out the Rinnai. 75%AFUE, 4 stage automatic modulation and two stage blower (quietest in the industry) and a programmable t-stat (on/off operation), remote, and you don't need to add controls. Our fireplace won't heat as well as our wall furnace either!

Bob Harper

shameless advertising, huh?

We get the picture Jack. You have a nice product you are proud of. I think it would be a little more appropriate to mention a line about the product then provide a link like this: www.fireplaces.com

Have a good day

Nick_16

No fireplace

I too would add a pannel rad. or the baseboard. Gas fireplaces aren't very efficient, usually around (70%), hopefully your boiler is more effiecient than that. Also, I but gas fireplaces in 3 areas of my home and in 8 years have had nothing but trouble with them even though I had the FIREPLACE people come and service them every year. Stick to hydronics.

Mitch_4

get a better contractor then

I have a direc vent unit 83% AFUE, other than cleaning the pilot and burner, I have had to do nothing to it for the last 6 years.

Vermont castings / CFM unit...does a beatiful job.I recommend them, I have installed litterally 100's of these units in all configurations. Never a problem. Best thing in my sales arsenal.

I also have sold and serviced Regency units too. I like them also, only problem was t-cpls at first.

Mitch

Bill_24

You could look into a hydronic fireplace insert.Looks like a woodstove but the heat is generated off the boiler with a coil. They have a feature of turning the "flame on or off" so when you're not home it will still heat. Then just turn the flame "on" for the fireplace look. The flame looks close to the real thing. Set it up as its own zone and set it to desired temp. Can't for the life of me remember the name of these but I did see one at a show once, preety cool. I'll have to go look for them and update later.

Hydroflame that's there name. Ya

Bill.

JohnWood1

The problem with mixing and matching millivolt and 24V

The fireplace will work fine but you will need to have a relay in the fireplace to take the 24VAC signal from the 2 stage stat and make the 750mA DC circuit to enable the heat.

Very easy to do. Make sure the relay is at or close to the gas valve of the FP to keep the millivolt signal strong. 24VAC travels better!

Bob Forand

Wall Radiant

AJ, Is it possible for you to use the walls or ceiling to put some extra tube in ? Why run higher temps to baseboard if there is no need. ...

Bob Forand

Wall Radiant

AJ, Is it possible for you to use the walls or ceiling to put some extra tube in ? Why run higher temps to baseboard if there is no need. ...

AJ3

Re: Wall Radiant

Everything is already rocked and I'm already running higher temps to the baseboard on the second floor. I pondered lining my faux chimney with radiant tubes but it would not have been enough to make up the difference.