pressuretrol wiring

amateurplumber

i have a burnham V904A boiler that gives steam heat and for hot water production it pumps to a coil in a hot water storage tank. the building is an 8 unit apt building in brooklyn ,ny.

i have examined the wiring and find it to be somewhat illogical. the steam production and hot water production are not independent. it seems that the prressuretrol is in the wrong place in the circuit because in the event that steam and hot water are being called for at the same time, when the pressuretrol reaches it's high setting it will stop the burner and the pumps that pump hot water through the coil even though the aquastat on the hot water storage tank may still not be satisfied. i suppose it is possible this may not matter too much if the time between the pressuretrol reaching its high setting (turning the burner off and the pumps also) and it's low setting (turning the burner and the pumps also on again) is not too long because then the hot water production will continue where it left off and since the boiler water will be way higher(220) than needed for hot water the pumps should quickly be able to bring the water in the storage tank up to the temperature (150) that satisfies the aquastat on the storage tank. but i was thinking that the diagram below labeled proposed wiring would make more sense, and should save fuel.

i am hoping someone more experienced could give their opinion on the wiring diagrams below.

also regarding the aquastat (the one on the boiler ) should it be set at 220 all the time? because that is what is efficient to make steam and if hot water only is being called for it wont reach much beyond 180 or so because before it can get any higher the aquastat on the storage tank will have been satisfied, in other words is it correct to say the setting is not important with regard to hot water production as long as it is above 180 or so?

sorry for the long post,

thanks in advance

AlexR

another amateur

Warning: I am not an expert.  I have a similar setup in my home, though my hot water loop is a baseboard loop rather than DHW.



I think your proposed setup is correct based on a quick look at your diagram (I didn't check the diagram against the relay wiring instructions you posted) and assuming you actually have three aquastats (one on tank, two on boiler).



One thing I disagree with:

> also regarding the aquastat (the one on the boiler ) should it be set

at 220 all the time? > because that is what is efficient to make steam

and if hot water only is being called for > it wont reach much beyond 180

or so because before it can get any higher the >aquastat on the storage

tank will have been satisfied, in other words is it correct to say > the

setting is not important with regard to hot water production as long as

it is above >180 or so?



If I understand what you're saying, I think you should set the aquastat on the boiler below 212.  You don't want to end up making steam if the system is just trying to make hot water, since you could burn a lot of fuel and potentially never hit 220 if the energy's all going into steam.   If your aquastat is as inaccurate as mine, be sure to watch the system in operation for a while so you can set the aquastat as high as possible without steaming.