Vertical header

[Biggles..]

Guys, just a quick question regarding the output side of a low loss header.

What we have is a heat only boiler with in built pump(pump not capable of delivering the flow required), so pipe this into a low loss.

On the output side have two circuits, 1 for heaing (currently 2inch iron)and 1 for hot water each with their own pump and controls.

Would each circuit require a zone valve also to ensure water cannot flow or would just a non return valve and the pump be enough to ensure no flow when no demand called for.

The last time i looked at one of these was as an apprentice so any help would be much appreciated.

 

[doitall]

Yes you should fit zone valves and non return valves if the pump heads are different as the larger pump can rob the smaller one.

see pic, and ask any questions.

 

[Biggles..]

Nice photo John, was hoping you'd answer.Why the bypass thought the header would act as that.

The 2inch iron is currently on a one pipe(unable to alter, listed building heritage etc) so the head will be different to that of the pump for the hot water.

Boiler will be a Keston C40 and the header is a Broag.

 

[doitall]

The byepass was needed in this case as we used a common pump.

In your case a by-pass maybe needed to lubricate the pumps unless you can interlook the pumps, boiler and zone valves.

Will you be using a shunt pump from the boiler through the header.

 

[Biggles..]

Intend to use the pump thats in built for the shunt before the header. Will this surfice.

15/50 for the hot water, and then need to size the current pump that drives the existing heating for the other zone (1960's 2inch iron single phase but thats all i know at present till its ripped out)

 

[doitall]

Yep the boiler pump is ideal as the shunt pump.

The heating will require a by-pass somewhere in the system, or you could consider a 3port compensator valve. do a google on ESBE valves.

 

[Biggles..]

Will do, had ordered a bypass with the rest of the materials.

Is there anything else that i'm missing John?

Thanks for your help.

Lee

 

[doitall]

No I think you have it covered.

If you want to send me the details I could knock you up a drawing.

 

[Onetap]

Guys, just a quick question regarding the output side of a low loss header.

What we have is a heat only boiler with in built pump(pump not capable of delivering the flow required), so pipe this into a low loss.

On the output side have two circuits, 1 for heaing (currently 2inch iron)and 1 for hot water each with their own pump and controls.

Would each circuit require a zone valve also to ensure water cannot flow or would just a non return valve and the pump be enough to ensure no flow when no demand called for.

No.

However, you might get nuisance gravity circulation through the secondary loop when there is no demand, so I would fit a zone valve to prevent that happening. Gravity circulation can open a swing-check non-return valve. Spring-check NRVs take more flow to open, but a zone valve will put a certain stop to the gravity circulation.

The whole idea of the low loss header is that there's negligible pressure loss (low loss) due to friction along the header. If the primary boiler and heating secondary pumps were on and the HWS pump were off, then the pressure difference across the HWS flow and return connections to the LL header pipe should be close to 0.

If you had undersized the low loss header so that there was a significant pressure loss, then the water will be driven along the HWS circuit, from the high pressure to the low pressure, despite the secondary pump serving the HWS being off .

PS Edited to change 'pressure' to 'pressure difference'.

 

[Biggles..]

Onetap, not sure about your second post? but thanks for the first reply.

Hopefully boiler, header, pressure vessel and pumps will be piped up tommorrow so hopefully get a pic taken.

 

[Biggles..]

Getting late and brain not switched on.

 

[Biggles..]

Pump came out with alot of persuation. Original pump was a 1.5 inch sigmund(green 85 watts). Tried to get grunfos to spec up the replacement for it but about as much use as a chocolate fire guard.Any suggestions?

Did manage to bridge the old pump space though with a handy bit of 42.

 

[Onetap]

Pump came out with alot of persuation. Original pump was a 1.5 inch sigmund(green 85 watts). Tried to get grunfos to spec up the replacement for it but about as much use as a chocolate fire guard.Any suggestions?

Sigmund pumps, aka Sigmund Pulsometer Pumps, now known as SPP. Try them for some info. Think they only do commercial stuff, so they might not want to spend time on something that won't result in an order.

Calculate the pump size; it wasn't necessarily the right pump for the appliaction in the first place!

 

[Biggles..]

Cheers for that, will look into it. Have come across the pumps before some green some grey but never known the full name of the company.

 

[heatmizer]

Yes you should fit zone valves and non return valves if the pump heads are different as the larger pump can rob the smaller one.

see pic, and ask any questions.

Can Anyone tell me what type of insulation products were used here?