Need help --been "cowboy'd"

[Gasguru]

you can use a combined Feed and Expansion pipe now (formerly you had to use two pipes).

Not so hasty, this is an old boiler and is unlikely to have an additional overheat thermostat. Some manufacturers allowed combined F&E but not all especially older models.

Remember in a fault condition the boiler will be boiling the water and will have trouble replenishing it with steam going up the feed pipe.

 

[JohnD]

needs someone who knows!

 

[andy28]

so, looks like i need a 2 pipe system, seperate feed and seperate vent, just to be on the safe side. I have the 2 x 22mm pies coming from the boiler. On one i've got the pump so i would take this to be the flow side. After the pump both T off, going to the down stairs rads and upstairs to i suppose the upstairs rads and the old cylinder.

Where would i T in the feed and the vent pipe. I'm assuming one of them goes before the pump, but is it the vent or feed, or doesn't it matter.

 

[JohnD]

both.

otherwise you will have a pressure difference between them

 

[andy28]

When you say both do you mean T the feed into behind the pump, then T the vent into the return. Then join both of them by T'ing the feed and vent so i have got a 'H' just above.

 

[JohnD]

no, I mean, on the suction side of the pump, two tees. One goes up and is the vent, bent over the top of the F&E; and the other runs up to the botom of the F&E, and is the feed. The feed is normally in 15mm and the vent is 22mm

I wish one of the CH guys would come in with a diagram.

 

[undercover]

Hi Andy.

I've just read your posts. I'm sorry this has happened and given us a bad name.

It may have not been entirely the plumbers fault. The vent pipe to your primatic could have been blocked for a while. Your leak just started off the process. I bet the plumber just simply began a straightforward drain down, not fully realising this and -whoosh there go's your primatic.

For now just do a swap over to an indirect system. Use 2 pipes to protect the boiler. Just before the pump add 2 T's. Take 1 up and over your new F&E tank. Use pulled bends. The other reduce down to 15mm and take this to your feed outlet. Connect up your indirect cylinder. Fill your F&E tank and add some inhibitor. Fill your rads and bleed from bottom to top. Fill the domestic hot water side and bleed the air out of all your hot water taps.

Will see you through until you replace your system next year.

 

[holty]

the usual rule is, the vent then the feed within 150mm within each other then the pump try this link it may help http://www.gasman.fsbusiness.co.uk/fully_pumped_systems.htm

 

[leakydave]

to drain a primatic cylinder I have had to shut off supply from header tank, run taps as much as possible, loosen the connection at the top of the cylinder and syphon out the water from the top with hose filled with mains water and thumb over end 'til ready to syphon. This sounds a real nightmare... primatic cylinders are 'ok' when they work but it is easier (and cheaper) to replace with indirect cylinder and f&e tank... (PS Ignore my name, it wasn't me that left the job in a hurry!!)

 

[Tim 77]

Tried again all this morning. Mobile still switched off.

Stick his number up on here, we can all try calling him then