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Main Forums => The Roundtable => Topic started by: Hawkmoon on March 06, 2019, 01:47:14 AM

Title: HVAC question
Post by: Hawkmoon on March 06, 2019, 01:47:14 AM
I'm being tempted to put a stove insert in the fireplace in my living room. The problem is that the house is a ranch, and the living room is at the far end from the bedrooms. The thermostat is in the front hall, directly outside the living room and separated only by a double wide opening (with no doors). A stove will do a great job of heating the living room, dining room, and possibly the kitchen ... but I'm concerned that the heat that gets into the hall will tell the thermostat no heat is needed. That will mean no heat for the bedrooms or bathrooms.

The house doesn't have central air, so the thermostat is a simple, 2-wire, heat-only thermostat. Would it be possible to install a second thermostat, at the opposite end of the hall, and wire it in parallel with the first one so the boiler will come on regardless of which one is calling for heat?
Title: Re: HVAC question
Post by: K Frame on March 06, 2019, 07:16:27 AM
Same kind of set up that my Aunt and Uncle had in their ranch.

First, I think you'd be far better off by removing the thermostat you're worried about and replacing it with a wireless thermostat back by the bedrooms if you really want to go that route.

Also, do what my Aunt and Uncle did... use a box fan, set on the floor in the hallway and pointing towards the fireplace.

This will move the cold air out of the back area of the house and push it to where it can be warmed by the stove.

The cycle will pull warmed air back toward the bedrooms and you'll get a more even heat distribution.

In other words, don't try to move the warm air, move the denser cold air.

I'm using that trick to help my pellet stove distribute heat more evenly and quickly.
Title: Re: HVAC question
Post by: charby on March 06, 2019, 08:44:01 AM
or just flip the switch for furnace fan from "auto" to "on" your thermostat.

What we do on bright sunny winter mornings where the sun in warming the living room via the picture window.
Title: Re: HVAC question
Post by: Ron on March 06, 2019, 09:18:02 AM
or just flip the switch for furnace fan from "auto" to "on" your thermostat.

What we do on bright sunny winter mornings where the sun in warming the living room via the picture window.

He has a boiler, I almost posted the same thing.

I like Mikes idea, box fan to push cold air at floor level into warm room.

You could also spend some money this summer and install zone valves with separate t-stats.
Title: Re: HVAC question
Post by: charby on March 06, 2019, 09:21:18 AM
He has a boiler, I almost posted the same thing.

I like Mikes idea, box fan to push cold air at floor level into warm room.

You could also spend some money this summer and install zone valves with separate t-stats.

I didn't catch the boiler, do what Mike said.
Title: Re: HVAC question
Post by: K Frame on March 06, 2019, 09:41:22 AM
Zoning is definitely a possibility if it's not zoned already, but that's a lot more labor intensive and expensive.

You'd need zone valves, possibly circulator pumps (depending on how it's piped), thermostats, and the pipe work.


"just flip the switch for furnace fan from "auto" to "on" your thermostat."

Obviously not an option with a boiler, but I've had the circulator fan on my heat pump's air handler on circulate for pretty much 24 years. It keeps temperature differentials between floors a lot more even and it also keeps filtering the air, which is a big consideration for me given my allergies and the fact that I have a dog who tracks in a lot of crap on her paws and fur.
Title: Re: HVAC question
Post by: MechAg94 on March 06, 2019, 10:03:24 AM
For fans, some of the smaller fans Lowes/Home Depot sells do a good job of directing air in a certain direction.  I used to use a fan to get better air flow into my bedroom before I replaced the A/C and they revised the ducts a little.  I had a little fan that did a good job of directing a flow stream through a doorway several feet away.
Title: Re: HVAC question
Post by: Hawkmoon on March 06, 2019, 01:16:27 PM
or just flip the switch for furnace fan from "auto" to "on" your thermostat.


What is this "switch" to which you refer?

The only switch in my heating system is the red emergency shutoff next to the boiler. I don't think I've ever seen a heat-only thermostat with an OFF-AUTO-ON switch.
Title: Re: HVAC question
Post by: K Frame on March 06, 2019, 01:32:57 PM
"What is this "switch" to which you refer?"

It's a switch that you don't have because you have a hot water heating system.

Forced air systems use a fan to distribute heated/cooled air by drawing it through return ducts, through a filter, and across the heating/cooling coils.

The fan can be set so that it only runs when the thermostat is calling for either heated or cooled air (AUTO), or it can be set to run continuously (ON). Normally went set to ON the fan will run at a lower speed, and ramps up to the higher speed when the thermostat turns the system on.

As I noted in a previous message there are some benefits to letting the fan run all the time. The drawback is that it uses electricity continuously when set to on.
Title: Re: HVAC question
Post by: charby on March 06, 2019, 02:28:43 PM
What is this "switch" to which you refer?

The only switch in my heating system is the red emergency shutoff next to the boiler. I don't think I've ever seen a heat-only thermostat with an OFF-AUTO-ON switch.

Mike explained it. Where I live boilers are rare in residential houses and most folks have a NG or Propane forced air furance.

When I see "central air" I immediately think of the air conditioning unit attached to a forced air furnace.
Title: Re: HVAC question
Post by: Scout26 on March 06, 2019, 04:27:57 PM
I have a Drolet insert in my fireplace in the living room.  There is only a hallway to the back bedrooms.  I simply close the doors to the unused bedrooms and make sure I bank the coals to the front of the insert, fully load it with firewood, and damper it down pretty low.  When I got up Tuesday morning the thermostat in the hallway said 71F and it was very warm in my back bedroom.   (I have the furnace set to 63F at night.)

I got this one about 2 years ago (i got the "Trio" which included the faceplate, blower, and exhaust kit for $1300)

https://www.menards.com/main/heating-cooling/fireplaces-stoves/wood-stoves/drolet-escape-1800-i-wood-burning-insert-500-2-100-sq-ft/db03125/p-1444444141020.htm

I wish I would have bought one 20 years ago.
Title: Re: HVAC question
Post by: 230RN on March 07, 2019, 01:51:14 AM
Apartment.  Baseboard hot water convection.  Found out that it layers in the room: stand up from the couch and it's all hot air up there.

Apartment, remember?  Can't install a ceiling fan. Got a little 10" fan and put it on the floor in the corner pointing straight up.  Cured the problem.

Punch line:  I call it my ceiling fan.  (Serves the same function.)

 You've been a great audience.  Don't forget to tip your server.
Title: Re: HVAC question
Post by: K Frame on March 07, 2019, 01:26:19 PM
Stratification can be really bad when it's really cold out. Friends of mine in Iowa have that problem and use their ceiling fans to combat it.

With the pellet stove I've installed I've noticed stratification on the second floor, but that's because I'm using the gravity cycle to distribute the heat.

I may end up putting a very quiet 6" exhaust bath fan in the living room ceiling to move some of the warm air out of the living room and dump it into the upstairs hallway.

Not going to do that until I get at least a year in, though.

That's one of the great benefits of in-floor radiant heating -- who gives a *expletive deleted*it if the heat stratifies when the entire floor is the radiating surface and the heat is washing up over you.

Because of that you can be extremely comfortable at much lower thermostat settings.
Title: Re: HVAC question
Post by: 230RN on March 07, 2019, 03:27:58 PM
Possible hint on small fans.  I've been running 220volt "Impedance Protected" fans on 110volts for years.  This, to boost the heat coming off the baseboard hot water pipes in certain areas.

They do not move a lot of air... they just sort of wave it along, but they are practically dead silent.  No, they don't overheat running on low voltage because they're "impedance protected," meaning the combination of their inductive reactance and their ohmic resistance will not allow enough current to flow to cause overheating.

I gave Son1 a couple of them to just sort of silently keep the air moving in some of his audio equipment cabinets. He's very happy with the result.

Terry, 230RN


Title: Re: HVAC question
Post by: Firethorn on March 08, 2019, 03:49:00 PM
Given that Hawk has a boiler system, I wondered if you could get a hydronic fireplace insert.  Apparently they make them over in Europe.

With that, you'd run the boiler water through the fireplace insert, then through the loop to the bedrooms.  Exact design would depend on zoning and design of the existing system.  

All you'd need would be something that tells the circulating pump to run when there's a sufficient fire in the insert.

http://www.aquaflam.cz/en/fireplace-inserts
Title: Re: HVAC question
Post by: K Frame on March 08, 2019, 04:00:14 PM
As far as I know, those types of units aren't available in the United States, which is kind of silly given how many fireplaces there are and now many people heat with wood.

Your fireplace is your primary source of heat and your boiler is an inline back up.


Years ago my music teacher designed his own house and one of the things he did was tie a loop in the fireplace that wasn't directly connected to the boiler system, but which transferred heat to the boiler system... sort of the reverse of an indirect water heater. I remember he said he had issues with getting the inspectors to approve it, but eventually did, and he pretty much heated the house that way for many years.
Title: Re: HVAC question
Post by: K Frame on March 09, 2019, 07:45:01 AM
The British also have cooking stoves (Rayburn is the big one I think) that can be plumbed into a home heating system. Looks like Rayburn is now manufactured by Aga.

Again, I don't think they are available in the US.