mixed up flow and return

[egginyourface]

hi all,

im not a plumber but was wondering what happens if you upgraded a boiler and mixed up flow and return??

i wired s plan programmer today and couldnt get the boiler to work properly. plumber said he may have mixed flow and return and thats we couldnt get any hot water working

ch would work for a few minutes then boiler would shut down

anyone ever seen this before??

the boiler is glow warm boiler, with honeywell programmer and thermostat

 

[benfisher]

To check if the F/R are round the right way fire the boiler up then get to the airing cupboard and see which pipe gets warm, the pipe going to the pump will get hot first if it's piped up right. If it is the return heating up first I'd be getting the plumber back straight away to pipe it up right, obviously never tested and commissioned the boiler, certainly wouldn't use him again.

 

[Blackcatgas]

yes Ive mixed up the flow and return before, fire up the boiler and then feel with your hand wether its the left or right hand pipe that gets hot first off the top of the boiler. Iam not sure which side is the flow on your glow worm, Id hazzard a guess its on the left.

Edit, Benfisher beat me too it.

 

[AWheating]

we have all done it, its when you cross the flow and gas you really need to start worrying.

 

[egginyourface]

another question is how can you tell which is the ch motorised valve and which is hw motorised valve?

 

[gaspastemania]

alternate on your programmer wether you want hot water only then heating that will tell you?
curious as to why your asking this tho,,,,bodged up have you???

 

[Blackcatgas]

the hot water motorised valve should conect into the cylinder coil tapping on the side of the big green/blue water cylinder in your airing cuboard or as they call it up north a "hot press"

 

[egginyourface]

im an electrician,,,, and was asked by the plumber to take old s plan programmer off and refit new one.

this is the first time i have ever had to do this. i disconnected everything and reconnected according to this diagram

S-Plan

realised that boiler needs a perm live so pulled this in. boiler is still playing up...

ie no hw and ch comes on for about 5 min then turns off

 

[gaspastemania]

does sound like the flow and return are linked back to front. if its firing up and cutting out then that does suggest that its gone pear shaped

 

[egginyourface]

we're going back tomorrow together and gona sort it,

i just want to get a bit of info on just incase its down to my wiring

 

[cjg]

don"t know on this boiler with out checking but if it has a flow switch then the boiler will(normally) only run correctly when the f/r are correct, but sometimes will fire then shut down on ch if wrong ,, if you know what imean

 

[fuzzy]

another question is how can you tell which is the ch motorised valve and which is hw motorised valve?

one pipe goes to the cylinder and one to the rads, just trace em

 

[egginyourface]

thanks all for the pointers. we sorted it.

flow and return were wrong way round and internal thermostat on boiler was set low so boiler only fired for a few minutes the shut down.

we know for next time

 

[kirkgas]

thanks all for the pointers. we sorted it.

flow and return were wrong way round and internal thermostat on boiler was set low so boiler only fired for a few minutes the shut down.

we know for next time

and that is the important bit, every day is a school day

 

[SafeGasInstall]

another question is how can you tell which is the ch motorised valve and which is hw motorised valve?

if you can tell better of not to wire them up any more

 

[egginyourface]

Why should i not try to wire them up? Through this experience i now understand how a s plan heating system works. My wiring was spot on!

I think theres a lot of plumbers out there that dont understand why we bond gas and water pipes to main earth but there still allowed to carry on

 

[SafeGasInstall]

might be plumbers you speak of but def not gas engineers ! aint that hard to wire it up !I did not know my self but I did Honeywell training where everything was explained ,and ever since 3 jobs wired up total save £600.00 for my business of not using electrician services

 

[egginyourface]

is that what sparks charge ?