heat exchanger temps

[ktm250rider]

Ive just hooked up my remote BBQ thermostat to monitor my water temp on the 5500. Incoming water is 180 (when boiler is at 180). Depending on calibration of a possible 1-2 degrees off, Im pretty happy with the incoming temp. Ive just put the 2nd probe on the output of the HX going towards the existing boiler. It seems to be only pulling about 150-160 from the OWB. Should I be loosing that much across the HX? We have hard water up here in NH, system has one season on it. I cant remember what my boiler was reading last year as a comparison.

 

[projectsho89]

Depending on the inlet water temp and the temperature of the return air, I see anywhere from 23 to 32 degrees F temp drop across my HX.

You're not "loosing" that much heat, that's how much heat is being transferred from the water to the circulating air.

A faster pump speed would "lower" the differential, a slower pump speed would "increase" the spread. Same with blower speed if you were to change it.

If you were to install a water flow meter and could determine what the rate of slow is, you could accurately determine how many BTUs were being transferred from the OWB water to your home.

Steve

 

[ktm250rider]

yeah I guess loosing was the wrong term. My real concern is that my air handlers seem to run much longer since the water going to the units (water to air heat exchanger) is only 150F. So, if I plumbed the OWB directly into my gas boiler, Id have 170-180 going to the air handlers.

 

[bigden]

lost temp

I've got a new 70 plate hx I'm not getting that kind of difference in mine. im wondering if im going to have the same problem as I'm in laconia and have hard water her to. but right now a month of running there is not that much of a fluctuation in mine being it is new.what make is your owb I've got the wood doctor.

 

[ktm250rider]

Its a woodmaster 5500. I think the HX is a 50 or 60 plate. Pretty sure its supposed to be 60.
So Ive read a couple posts about people plumbing directly from the OWB into their house boilers even though the house boiler is at 15 psi. THat seems like a better idea than replacing the heat exchanger.

 

[projectsho89]

A better idea would be to load the systems with SOFT water so you don't have to worry about hardness minerals causing problems.

If you don't have a whole house softener, you can use one of the limited-use softener cartidges to remove the minerals (usually calcium carbonate) for your boiler fill.

If you have a pressurized boiler, you'd better stick with an exchanger...or else.

It would also be a good idea if you fully described your system, we may be thinking in different terms.

Steve

 

[tanker]

A better idea would be to load the systems with SOFT water so you don't have to worry about hardness minerals causing problems.

If you don't have a whole house softener, you can use one of the limited-use softener cartidges to remove the minerals (usually calcium carbonate) for your boiler fill.

If you have a pressurized boiler, you'd better stick with an exchanger...or else.

It would also be a good idea if you fully described your system, we may be thinking in different terms.

Steve

when you hook up direct to your house boiler,you are vented through your owb.won,t build up pressure to explode.I have ran mine this way now for 4 years no problem.

 

[projectsho89]

when you hook up direct to your house boiler,you are vented through your owb.won,t build up pressure to explode.I have ran mine this way now for 4 years no problem.

If one doesn't know what they're doing, it can become both complicated and dangerous.

There are too many variable in the OP's description that are not known which are needed to set up a safe and effective system.

Steve

 

[ktm250rider]

Well, i dont know if its actually pressurized. Its a propane fired Weil-Mclane boiler. There is a dial on the front that shows the operating pressure. Just about under 15 psi. That was initally installed to feed my 3 air handlers with water to air heat exchangers. 1 for first floor zone, 1 second floor and 1 master bedroom. When I added the OWB, I put in a 50 or 60 plate (wp4-54 model number). I also have a radiant system that is used to warm the tile areas such as the kitchen and bathrooms. The OWB is a woodmaster 5500 with about 80 feet of pex pipe.
I could feed the boiler with "soft" water, but will that clean up my heat exchanger if its crudded up?
My neighbor installed his OWB without a HX with a pressurized boiler as well. No problems so far.

 

[tanker]

Well, i dont know if its actually pressurized. Its a propane fired Weil-Mclane boiler. There is a dial on the front that shows the operating pressure. Just about under 15 psi. That was initally installed to feed my 3 air handlers with water to air heat exchangers. 1 for first floor zone, 1 second floor and 1 master bedroom. When I added the OWB, I put in a 50 or 60 plate (wp4-54 model number). I also have a radiant system that is used to warm the tile areas such as the kitchen and bathrooms. The OWB is a woodmaster 5500 with about 80 feet of pex pipe.
I could feed the boiler with "soft" water, but will that clean up my heat exchanger if its crudded up?
My neighbor installed his OWB without a HX with a pressurized boiler as well. No problems so far.

When you tie into your present boiler,you make it an open system,you shut off the auotfill valve and run your heat from your owb.as long as you are going through your owb,you are not running a pressurised system,my oil boiler will kick on if water temps get low enough,(low temp aquastat) and will run on its ownand will keep your owb from freezing as lomng as your circulation pump is running.I can put my boiler back on line and pressurisedin less than 5 min by shutting off 2 valves to the owb and turning on the4 auto fill.Simple process and install for someone who is halfway knowledgable about tools and plumbing.Just remember to keep the vent on your owb open.