Supplying extra f&e tank from one pump.

[Honeyhember]

Hi guys,

I’ve got a situation where the customer has the one cold water storage tank in the loft supplying both the HW and CH. It’s fed from a borehole and using a Stuart Turner float switch in the tank and pump in the basement. The customer wants a separate f&e for the CH. Is there a way you can fit a secondary float valve and use the same pump? If so how is it wired back? Or do I need to fit second pump? I’ve never had much to deal with float switches and pumps before so any help is welcomed.

 

[John.g]

Assuming F&E tank near/adjacent to the CWST, can you not just install a T with isolation valve from the CWST float valve feed and run another feed line to the F&E Ball Cock, admittedly you can only fill the F&E tank when there is a demand for cold or hot water but once filled the F&E tank should rarely need any water and because the pump will be cutting in/out multiple times/day anyway then there should be no problem?.

 

[SJB060685]

But if tee'd off after pump then when CWST fills you'd be pumping against a closed circuit?

 

[John.g]

The CWST fill valve only controls the pump so yes, there will be some pressure at the F&E ballcock (the same as if you were supplying it from the mains) with the pump running, but you won't be dead heading the pump because when the CWST float valve is satisfied, the pump stops.

 

[centralheatking]

Hi guys,

I’ve got a situation where the customer has the one cold water storage tank in the loft supplying both the HW and CH. It’s fed from a borehole and using a Stuart Turner float switch in the tank and pump in the basement. The customer wants a separate f&e for the CH. Is there a way you can fit a secondary float valve and use the same pump? If so how is it wired back? Or do I need to fit second pump? I’ve never had much to deal with float switches and pumps before so any help is welcomed.

I see that this is a bit ...off grid type thing...but I know water regulations preclude this set up and in my
very open opinion about things...I think this set up is unsafe. I get all the bore hole stuff..been there but
safety is paramount.
I wonder if there is space adjacent to the tank in the loft to install an intermediate equal level tank with air break etc. to feed for the ch. Dont do electric operatec things unless you mus
think simple its safer ....the new mantra ...and I know as I design HVAC stuff is...
'complicated is easy....simple is hard' ...and I would check this tank and sanitise it
centralheatking

 

[John.g]

Is it unsafe because of the bore hole water?, because otherwise, technically at least, it is the same as supplying both tanks from the mains? or maybe you are commenting on the original set up, ie one tank supplying both the cold&HW and the CH which should definitely be a no no.

 

[centralheatking]

Is it unsafe because of the bore hole water?, because otherwise, technically at least, it is the same as supplying both tanks from the mains? or maybe you are commenting on the original set up, ie one tank supplying both the cold&HW and the CH which should definitely be a no no.

BoreHole water or Spring Water like we had in Somerset is safe and lovely esp. when uv treated before use. Its the shared intermediate tank thats my issue. Drinking water from whatever source must be
complely sep from non potable water by various means usually by class air breaks depending on the quality of the other side. centralheatking

 

[SJB060685]

What part of Somerset CHK?

 

[John.g]

So a separate F&E tank doesn't meet this criteria?, the suggested feed for both is common but there will be a air break between the F&E tank water surface and the ball cock outlet, also the F&E overflow should ensure (as always) that this air break is maintained with a overflowing tank.

 

[centralheatking]

What part of Somerset CHK?

We had a smashing spring water supply from Solsbury Hill ...of Peter Gabriel fame for years.
Except when it froze up one winter for 2 weeks about 1983 ...centralheatking we had to go down to the White Hart for a whole fortnight...happy days

 

[SJB060685]

I'm taunton in somerset

 

[Honeyhember]

Thanks for your replies guys. Yes it will be next to the current CWS tank, i think t-ing it across to feed it is the best way. I couldn’t get my head around how it’d work with calling for and shutting the ballvalve off to the new f&e but that makes sense. Yeh the current set up is definitely wrong that’s why customer got in contact with me. Will soon have it sorted, thanks for your help.

 

[fixitflav]

The CWST fill valve only controls the pump so yes, there will be some pressure at the F&E ballcock (the same as if you were supplying it from the mains) with the pump running, but you won't be dead heading the pump because when the CWST float valve is satisfied, the pump stops.

It's not a fill valve onthe CWST, it's a switch as in the original post. I think your suggestion is the way to go. The inlet to the CWST needs to be higher than the F/E tank inlet, but that should be the case anyway.