Staddy
New Member
I am losing my domestic hot water. High delta T! Advice wanted please! I have an old duplex house with insulated siding. A manual J says looses roughly 90,000 btu. Each unit is 2 bedroom 1 bath 1000 square feet. It is two stories. Their is a 118000 btu Burnham p206 boiler in the cellar with a Taco 007 for six zones operated by zone valves. Two of the zones are 41 gallon indirect hot water heaters for each unit; an Amana ERGW0012 and an Amtrol Wh-7P. The Amitrol Wh-7p is the only one I could find info on so far. It has total head of 6 and requires 4 GPM. The manual recommends using a dedicated circulatory pump or a full port valve, but it is plumbed using a standard valve. If using a full port valve it requires 3 GPM for each zone. 3 gpm x 6 zones is 18 GPM @ 6 feet of head. Using this data a pump chart indicates my Taco 007 is not enough pump. The other 4 zones heat the house with ¾ copper tubing and fin tube. My long longest zone is around 130 feet and my two shortest are around 100. I calculated feet of head for long loop with a delta t of 30 for the indirect hot water tanks. 130 x 1.5 x .04 = 7.8 ft of head. This would indicate my pump is too small, however, I talked to two hvac guys that didn’t seem to think a 007 could be too small. Also, I’m not sure how well the system ever worked, but surely it must have. I bought it in summer and I had heat off in rental unit while I remodeled. Now I cannot seem to get domestic hot water to my faucets and heat to all zones. I thought the problem was air so I eliminated all leaks and added some automatic bleeders to all zones. I also moved my 007 to the supply side, and the impeller is fine. Pump is in working order. The supply temp is about 185 and the return is only 110. I have 22 PSI coming into the boiler and I have plenty of pressure at the bleeders on top zone. What should I do to improve my system?
