swaped cylinder now water wont circulate ????

[bmx]

ok swaped the old gravity fed cylinder for a Range presurised cylinder. the hot and cold work brilliantly now , but the flow from the boiler is not going round the primary coil. it is piped up exactly the same as it was in the old cylinder (all i had to do was extend the pipes by about 10 inch) the hot flow gets to the inlet side of the cylinder, but the outlet pipe doesnt get warm. is there a chance the system needs a better pump because the new cylinder has twice as much primary coil? or is there another answer. the boiler is an IDEAL Classic. i thought that it would just be a straight swap, cant really understand it

 

[lorraine]

Hi

i'm no expert with unvented - in fact i'm not an expert at all!

Is there any flow going through the outlet at all? if there is then the heat exchanger might be that efficient that all the boiler heat is being transfered to the hot water.

if there is no flow or flow thats known as a "slug" or is it mist - i can't actually remember, you may have to bleed the pump.

Lorraine

 

[ArtfulBodger]

So presumably with just HW the boiler will either trip out or shut down in a matter of seconds? if not, the heat must be going somewhere - is there a bypass on your system anywhere?

 

[ChrisR]

If you're trying to heat a typical unvented cylinder by gravity circulation, forget it! RTFM!
Lorraine is into fundamentals of how things work so she'll soon work out why and be delighted, I'm sure, to tell you!

 

[bmx]

If you're trying to heat a typical unvented cylinder by gravity circulation, forget it! RTFM!
Lorraine is into fundamentals of how things work so she'll soon work out why and be delighted, I'm sure, to tell you!

basically its a like for like swap. except the new cylinder is stainless steel and has a lot more primary coil. it worked before so why not now? i waited around for an hour and a half and the hot water at the tap was slightly warm.

 

[ChrisR]

its a like for like swap

No it isn't.

Buy a diverter valve and replumb.

 

[bmx]

its a like for like swap

No it isn't.

Buy a diverter valve and replumb.

what is a diverter valve ?
why do think its different to the old coil?

 

[ChrisR]

what is a diverter valve ?

AAAArgh! Read all about heating controls here http://content.honeywell.com/uk/homes/catalogu.htm then Y plan specifically.

why do think its different to the old coil?

RTFM!

 

[Bahco]

Is this an unvented cylinder?

Why didn't the installer (with the relevant certificate) set it up properly?

You didn't mean that you swopped it yourself did you ?

There are safety features on an unvented which have to be installed properly as they can be very dangerous

 

[bmx]

yep swaped it myself. there is no problem with the presurised side of things

 

[gazthepottertonengineer]

not at the moment

its only when things go wrong that these safety features come into efect and stop your house blowing up

 

[ChrisR]

there is no problem with the presurised side of things

How would YOU know? As you're obviously incapable of Reading The Manual (RTFM), which says, in the right section, in English:

The primary circuit must be positively pumped. Gravity circulation is not suitable.

 

[lorraine]

Hi Everyone

Bahco - do you need a certificate to install an unvented cylinder? I thought anyone could do it. its just a matter of installing the relavent expansion vessel and pressure relieve valve I assume?

Could he not get away with a 3 port mid position valve or must it be specifically a diverter valve? or even 2x 2port valves?

Lorraine

 

[Gasman1015]

How do you know there is no problem, you have'nt managed to get it hot yet.!

 

[Bahco]

yep swaped it myself. there is no problem with the presurised side of things

I bet you do your own gas work too

Get it checked properly for the sake of your family.