please help!

[caveyuk]

Hello

I have just upgraded our semi gravity to a somewhat kind of working y plan system but i am having some problems which i think is to do with where the pump is situated.
Setup is a potterton kingfisher 2 boiler with 1 x flow and 2 x returns(1 from hot water cylinder and one from rads). I left the pump where it is which is on the return from the rads. I installed a 3 port valve. The vent is on the flow prior to the 3 port valve and the feed is on the return from the cylinder.
The problem i am having now is that when just HW is on the flow goes up vent pipe and into the header tank.
I attach pictures to help explain a bit better.
In order to remedy this as i think the pump is in the wrong place, should i fit a pump just before the valve?
Also are the vent a feed pipe connections in the wrong place, if fitting a pump to the flow then maybe i could connect the vent and feed pipe prior to the pump and maybe on the old connection to the rads?
FLow and return from cylinder is all 28mm which is a right in the you know where.
Anyways here are the pictures and i would appreciate any replies/advice on my situation.

Thank you ever so much!

 

[kevplumb]

pump on the flow before the valve
feed and vent within 150mm of each other before the pump

 

[corgiman]

if you are thinking of taken this up full time cavey

I would advise the lads to purchase shares in prestex right NOW


gawd you love a few compression joints dont ya

 

[Gas2Air]

Having stopped laughing now at the pics , may i post my advice.

Basically your setup is under positive pressure from the original pump position. Ideally you need the open vent (straight as possible) then cold feed to fit the pump on the flow after them.

The cold feed then acts as a neutral point and the system has equal pressures.

 

[sambotc]

Personally i would combine the cold feed and vent (ie tee the cold feed into the vent) then in between where the vent tee's into the flow from the boiler and the 3 port valve fit the pump.

Also get yourslef a blowlamp it will cost you less than all those compressions!

sam

 

[Gasguru]

A combined feed and vent may not be appropriate (or safe) for this boiler unless the additional overheat thermostat kit is fitted. It may not be approved for this arrangement either.

 

[sambotc]

By combining the cold feed and vent, i mean't at the point where they tee into the flow pipe. The reason for this was to save space to allow room for the pump to fit inbetween the fitting that are already in place.

This would not cause an unsafe sitation and also keep the 2 within 6" of each other.

 

[namsag]

It would have been cheaper to pay someone to do it than buy all those fittings. Saturday morning in any merchants and you see the diyer spending a small fortune on fittings etc. Doesn`t help when the guys behind counter play a game of lets see how much we can get them to pay.

 

[Jesus H. Christ]

The problem i am having now is that when just HW is on the flow goes up vent pipe and into the header tank.

I know what everybody is thinking, so here I am.

 

[caveyuk]

Thanks for all your advice. The reason i went for compression is i don't generally like using blow torch in such a confine space and believe me it is confined considering i can only just wedge myself between the cylinder and wall.
Anyways, today is the day and i need to get this sorted so i think i shall be doing as sam suggests and tee the cold feed into the vent. Cut out the pump from its original position and put that between vent/feed and 3 port valve. The boiler does have an overheat thermostat as that is what highlighted the problem to me as it had shut down.
Anyways, i will post more photos at a later stage and let you all know how i get on. Hehehe!

 

[caveyuk]

Right, so have done all that. Have now moved pump from return on rads to the flow just before 3 port valve, feed and vent come in prior to that.
Turn on hot water and boiler is cutting out due to overheat. I can't see what is wrong now?!?!

 

[caveyuk]

Aha! Didn't bleed pump doh!
Seems to be working at the mo!