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[buckgrunt]

When I first installed by outdoor wood furnace (CB-2300) 7 years ago,  CB recommended that I install a thermostat by-pass valve, which only allows wood furnace heated water above 150 degrees to reach the heat exchanger.   I still don't understand why this is needed and I am thinking of getting rid of it after this heating season as it has malfunctioned several times.  Can someone out there tell me why I need this and what would happen if I removed it ?......

[E Yoder]

That valve prevents cool return water from making a cold spot on the firebox or exhaust which could cause condensation and corrosion. If your return water temps stay high enough you could probably get by without it.
The valve would allow the furnace to heat up quicker as it wouldn't allow flow to go to the building until it's up to temp.
I don't use them myself. But I'm not installing CB's. They might not like it to be removed?

[mlappin]

That valve prevents cool return water from making a cold spot on the firebox or exhaust which could cause condensation and corrosion. If your return water temps stay high enough you could probably get by without it.
The valve would allow the furnace to heat up quicker as it wouldn't allow flow to go to the building until it's up to temp.
I don't use them myself. But I'm not installing CB's. They might not like it to be removed?

Meh, I know of a few CB’a in the area, soon as the warranty is done the thermostatic valves usually hit the scrap barrel first time they act up.

[bowood]

My understanding is that constant temperature is important for the CB to prevent condensation and thus corrosion.  So having the bypass helps you avoid putting a load pulling heat out of the boiler too early when warming up or after it has cooled down.  I have a propane backup so I removed the bypass.  I want the propane boiler to pull heat into the wood boiler on the rare chance I have the fire out.  I.e. removing the bypass helped me keep the CB at constant temperature.  In fact I believe the manual said this is one of the only cases where they actually recommend removing the bypass.

[wreckit87]

I'm going to agree with Yoder. Have you monitored your supply/return temps at all? You're going to want to stay above 140 on the return to avoid condensation. If you are able to maintain a >140 return, I would definitely remove it if it's troublesome. Most I've talked to around here just keep them around in case of warranty issues and throw them back in, but I wouldn't advise cheating that thing CB calls a warranty. It is a good tool for boiler protection, but they do have a bad tendency to malfunction. Far as I know, CB is the only MFGR that requires them so I wouldn't worry too much about removing it if your system is up to par otherwise

[real bill]

Mine got to acting up and not enough heated water was getting to the heat exchanger, so mine was removed.  Now everything works a lot better, a lot more heat coming through.

[aarmga]

That valve prevents cool return water from making a cold spot on the firebox or exhaust which could cause condensation and corrosion. If your return water temps stay high enough you could probably get by without it.
The valve would allow the furnace to heat up quicker as it wouldn't allow flow to go to the building until it's up to temp.
I don't use them myself. But I'm not installing CB's. They might not like it to be removed?

Meh, I know of a few CB’a in the area, soon as the warranty is done the thermostatic valves usually hit the scrap barrel first time they act up.

So the day after you buy one correct?

[mlappin]

That valve prevents cool return water from making a cold spot on the firebox or exhaust which could cause condensation and corrosion. If your return water temps stay high enough you could probably get by without it.
The valve would allow the furnace to heat up quicker as it wouldn't allow flow to go to the building until it's up to temp.
I don't use them myself. But I'm not installing CB's. They might not like it to be removed?

Meh, I know of a few CB’a in the area, soon as the warranty is done the thermostatic valves usually hit the scrap barrel first time they act up.

So the day after you buy one correct?

What they do is beyond me. Like mentioned already, if your system is designed correctly the return water shouldn’t be below 140 anyways. It’s a cute ideal, I think P&M recommended using one as well just wasn’t part of the warranty though.

[aarmga]

Exactly what I was thinking.