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[kayakerski]

Good morning everyone. Yesterday I bought 2 Honeywell GT162 temp guages that I want to install soon. They are 1/2" NPT thread and the probe (for lack of a better term) is 2.5". I plan on installing them into 3/4" black iron T fittings.

Does it matter how far the probe protrudes into the 3/4" line? I don't want to restrict flow.

Thanks,

Gregg

[slimjim]

You should get long neck tees that are specifically desgned for temp probes, they keep the probe in the well without restricting flow and with only 3/4 inch lines you don't want to restrict flow.

[kayakerski]

Thanks!

[slimjim]

Were you able to find the long neck tees

[kayakerski]

No but between the T and a reducer I was able to make it work.

[slimjim]

Well, did it help.

[kayakerski]

Well I'm glad I have them installed but I'm still not happy with my system. Last night the boiler ran for about 25 minutes and the return temp gauge got down to 110f. It seems like this happens once or twice a day. Other than that my delta t is about 20-30f (I hope that term means the change in temp between supply and return). I don't know if there is any way to fix those low return temps. It seems like it happens when the boiler has been dormant for awhile and there is a call for heat and my oil boiler fills with cool radiator water. I know I did alot better last year when daytime temps were below about 20f.

I guess I really need to get that aquastat in order to keep my boiler from coming on. On an additional note, I was reading up on the Honeywell 6006c-1018 aquastat and the say a minimum pipe dia of 1" is needed for accurate temp reading on a strap on aquastat. I only have 3/4". I would think it will still be ok for what I'm trying to do? I will just have to adjust it up or down a little in order to have it turn the oil burner on when owb supply line temps get down to 160. Hopefully it's just that and the smaller pipe does not make irratic readings.

Has anyone ever used a strap on aqustat on 3/4" iron?

Gregg

[slimjim]

The 3/4 inch iron is more than likely a big part of the problem if it is what you are running int othe oil boiler, think about it your heat zones are as well 3/4 inch, when they call for heat, they are dumping as much cool water back into the oil boiler as is coming from the wood boiler especially if your heat zones have cast iron rads and have been sitting dormant most of the day and are at ambiant temps, some of those rads will hold 30 or 40 gallons of water.

[kayakerski]

Hmm, I see. Actually my supply lines going from my oil boiler to the radiators are acually much larger than 3/4". I think 1.25-1.5" copper going out of the boiler but there are several 2" iron lines running around in my basement. The lines going to the radiators seem to be 3/4" though. Thats alot of water! 5 cast iron radiators and 3-4 baseboard units that dont seem to work well (I probably should try to fix them but we run a wood stove in that area anyway so I really dont want to run them). Thats all on the first floor. Upstairs there are 4 more cast iron radiators.

There is probably alot more going on here than I'll be able to fix without redoing EVERYTHING. I'm still saving alot of money now so I guess I can live with the issues I have as long as I'm not hurting anything.

Gregg

[slimjim]

Yes that is a lot of water, you will need to either limit the return temps to the boiler with a mixing valve or severely increase water flow from the wood boiler, maybe both.

[kayakerski]

Ah, more to ponder slim.

I'll look into both of those options and have more questions I'm sure.

The pumps you suggested (bumblebee or alpha) seem like cost effective options for increasing flow. I wonder how much that will help though since it seems like when there is a call for heat, ALOT more water comes back to the oil boiler than the 5-10 gallons it probable holds. I assume that's where a mixing valve comes in?

Gregg

[slimjim]

Yes, exactly, there is a lot of cold water up there in those rads, you may need to limit the amount of it coming back at one time with a mixing valve.

[kayakerski]

Ok, I think I understand the theory behind the mixing valve because I have a thermostatic mixing valve installed in my owb supply line as per central boiler.

I believe that one makes it so owb supply water less than 150f goes back to the owb for reheating in order to protect the boiler from low return temps. Is that also mixing supply water with my return water from the oil boiler  that is below 150f? If so then that low temp return water that I'm worried about should be ok, right?

Anyway, where would i install a mixing valve? In the return line to my oil boiler I assume. If thats the case, where would it send water that is below the set temp?

Gregg

[RSI]

Is your boiler able to maintain temperature or is it dropping low there too?

[slimjim]

Good question RSI that will certainly show the 3/4 inch is not large enough volume to work the wood boiler to it's capacity