Gravity fed to fully pumped

[newcomers]

Went and looked at a job today. The fella is redoing his kitchen and currently has a floor standing boiler in the kitchen, which is gravity fed hot water. He would like this removed and a wall hung boiler put in. He also has a pump on the shower in the bathroom, which has all now been boxed and tiled in

My questions are these:

The flow and return to the cylinder is 28mm.....could I reduce these onto 22mm and put a gat valve on the return of the cylinder?

Would the current cylinder be ok to use (approx 20 years old), I would I be better off recommending a new cylinder?

Because of the pump to the shower, does this mean he cant have a combi because of the mains pressure going to the pump?

In this type of situation (gravity hot water), is the cheapest and easiest option (which is what he wants) to put an open vent boiler in, along with re-positioning the pump, and adding a 3 port, r/stat and cylinder stat?

Thanks

 

[weareleeds]

Make sure you configure cold feed & expansion correctly

 

[lor]

if u keep the cylinder you can keep the shower pump.
if u fit a combi then u cannot used a shower pump(like u say cos u cannot pump mains pressure.
if u r pumping the supply to the cylinder u can reduce the pipe to the cylinder to 22mm (but why bother)
when converting to fully pumped you may need to relocate the cf & ov pipes to before the 3 port.
I suppose you can keep the gravity cylinder but the heat transfer rate will be much slower than a new BS cylinder, also the insulation will be inferior to a BS one.

 

[Soggy_weetabix]

Alternatively, convert to a 'C' Plan

David

 

[Softus]

My questions are these...

This is a bit odd - you're undertaking a major installation, but you're asking some very basic heating system questions.

 

[corgiman]

soft leave the poor wee lad alone

if you are hanging a new boiler it is probably part l compliant ergo the cylinder MUST also be part l compliant so it must be changed

as soggy says why not a c plan?

hello lor long time no see have a nice christmas mate?

 

[newcomers]

Whats c plan?

Ive only ever heard of s and y!!

 

[Softus]

Whats c plan?

See http://content.honeywell.com/UK/homes/Sundial.htm
and http://content.honeywell.com/uk/homes/systems.htm.

 

[newcomers]

So are you saying to basically keep the system as it is (gravity hot water, pumped central heating) and just stick at cylinder stat in and a 2 port on the hot water side?

Wouldnt it just be just as easy to stick a 3 port and have pumped hot water too? The pump will have to be moved from its existing location anyway

 

[Paul Barker]

The positions of the cold feed and open vent on a gravity system are different to that for a fully pumped system.

However if the existing pump is on the return, the cold feed is on the bottom of the cylinder primary and the open vent on the top, I have found that it works to put a second pump on the dhw return and two relays. It's beyond the realms of someone who has to ask the question to organise though.

You could combine the two returns put the pump after they combine and use two zone valves on the individual return's prior to the pump, wire it up for S plan. It should work.

 

[newcomers]

How about if I went fully pumped with a 3 port and pressurised system, that would be quite straight forward wouldnt it?

 

[fitz1]

hasnt the 2 port on the hot return have to be a permanantly open one and only closes with power.

 

[newcomers]

hasnt the 2 port on the hot return have to be a permanantly open one and only closes with power.

I wouldnt have a 2 port, id have a 3 port

 

[Paul Barker]

Sounds good.

 

[newcomers]

Sounds good.

is that a serious "sounds good" or a sarcastic "sounds good"?