Heating System

steve4545456 · May 13, 2009

Hi there, I,ve just joined this site in the hope I can get some help with a job that I,m doing. Its a standard fully pumped heating system, three zones (one for hot water, one downstairs heating and one upstairs heating) All controlled by a three channel timeclock. The hot water is controlled by a tank stat, the downstairs heating is controlled by a room stat and the upstairs heating works off the clock alone. There is a two port valve for each zone. My problem is that the plumber has installed an additional pump, due to the size of the house. So no matter whether the hot water or the central heating calls for heat, both pumps are running. He reckons with the way he has it plumbed, the other pump will be pumping against nothing and could eventually burn itself out ,if its constantly running. So I need a way of one pump knocking off whilst the other is running and vice versa. Obviously if it were only the one pump it would be happy days but this is new to me and any advice would be much appreciated. cheers.
steve.

sparks1234 · May 13, 2009

chuck a couple of relays in

silva.foxx · May 13, 2009

Sounds familiar...albeit different.

http://www.electriciansforums.net/e...l-regulations/5808-heating-control-pumps.html

sparks1234 · May 13, 2009

doesn't it just......oh no not again

ajelec10 · May 13, 2009

Hi the upstairs heating circuit shold also have a thermosat fitted to comply with part L, would like to know how the plumber has installed the new pump. i think that the pump should just be installed in parrell with the old to increase the pumping force so the wiring should also be in parrell with the old pump and come on either with the boiler or when the boiler calls for the pumps to run.

silva.foxx · May 13, 2009

Take a look at this example of 'S' plan wiring from Honeywell.

I take it that the zone valves have the feedback contact.

Did the plumber wire it in?

Can you state the position of the pumps with the system circuit?

Are the pumps wired from the boiler or the timeclock or elsewhere?

Is the additional pump just for the upstairs circuit or just added to the current pump?

Did the plumber state the situation where the pump could be pumping against a dead-end ie. if the rads are on TRVs (thermostatic valves) and become satisfied so close???

Regards

s.f

steve4545456 · May 14, 2009

Hi there, thanks for your reply. You say relays can be used for this situation. All my connections are done via a wiring centre local to valves and pumps. Can you instruct me what way to incorporate the relays.

silva.foxx · May 14, 2009

I'm afraid you'll have to wait for my ESP to kick in!

Give us a clue, eh?

We need to understand your control situation. You need to understand your control situation. This may be able to be done without relays if we only knew your current set-up.

For starters...where in the system is your additional pump located and in what scenario could it pump against a dead end?

Why do you want one pump to run when the other one isn't?

Surely each pump should run exactly when required, and stop when neccessary.

Hopefully Gypsy Rose Lee has finished with my equipment!

Come on, Steve...help us to help you.

Regards
s.f

Guest123 · May 14, 2009

steve4545456 said:
He reckons with the way he has it plumbed, the other pump will be pumping against nothing and could eventually burn itself out ,if its constantly running. steve.

Tell him to do properly then, by his own admission he's done it wrong why should you pick up the pieces. As has been stated already both pumps should work together if it's to provide more pressure into this system.

steve4545456 · May 17, 2009

Ok I,ll start again, Both pumps are situated in the boiler house. There is a two port spring return valve on each of the zone 1 (d/s heating) zone 2 (u/s heating) and hot water circuits. All my wiring goes back to this boiler house and terminataions are made through a standard wiring centre. Pump 1 is plumbed in before the valves for zone 1 and hot water (it pumps for them) and pump 2 is plumbed in before the valve for zone 2 and which solely is for the upstairs heating. Btw this is a four story house with a basement coversion from a cafe into living quarters so theres a lot of extra rads downstairs. So at my timeclock, if I call for zone 1 or hot water the respective valve opens and the burner and pump (s) start running. But my problem is that due to the switch wire connection at the wiring centre being the same for each pump along with the burner, pump two will also come on (with u/s heating valve closed) effectivly pumping against a closed valve. The same goes for if I have just the u/s heating on the two valves for d/s heating and hot water are closed and the pumps pumping against them. So my problem is separating the two switch wires to the pumps so that either or will come on with the burner. I,m sure theres an easy answer to this problem. At the mo Im have all three valves manually open and no matter whats switched on at the clock, the whole house is cooking.
regards steve

bcm_spark · May 17, 2009

Me thinks you have answered your own question. You need a seperate switch wire for each pump so that it only pumps when the respective zone is called. Why pump hot water round the upstairs heating if you only want the downstairs on?

Traineenoob · May 18, 2009

sounds like your in a little to deep lol

I do y plan heating systems but aint got a clue what you trying to do here :-S

bcm_spark · May 18, 2009

How are you getting on with this have you sorted it?

silva.foxx · May 18, 2009

steve4545456 said:
Ok I,ll start again, Both pumps are situated in the boiler house. There is a two port spring return valve on each of the zone 1 (d/s heating) zone 2 (u/s heating) and hot water circuits. All my wiring goes back to this boiler house and terminataions are made through a standard wiring centre. Pump 1 is plumbed in before the valves for zone 1 and hot water (it pumps for them) and pump 2 is plumbed in before the valve for zone 2 and which solely is for the upstairs heating. Btw this is a four story house with a basement coversion from a cafe into living quarters so theres a lot of extra rads downstairs. So at my timeclock, if I call for zone 1 or hot water the respective valve opens and the burner and pump (s) start running. But my problem is that due to the switch wire connection at the wiring centre being the same for each pump along with the burner, pump two will also come on (with u/s heating valve closed) effectivly pumping against a closed valve. The same goes for if I have just the u/s heating on the two valves for d/s heating and hot water are closed and the pumps pumping against them. So my problem is separating the two switch wires to the pumps so that either or will come on with the burner. I,m sure theres an easy answer to this problem. At the mo Im have all three valves manually open and no matter whats switched on at the clock, the whole house is cooking.
regards steve

So what controls the temperature upstairs? Is there a room stat upstairs or are all the rads on TRVs?

Does the u/s heating have it's own channel on the time clock?

Try this ragged attempt using two relays in parallel with relevant MVs so each pump is switched in when their MV opens.