Motorised Valve

[darrenj]

My radiators were getting hot when I selected hot water only.
I was advised it was the motorised valve that was blocked, I changed this yesterday.
The motorised valve I took off was a Honeywell and I replaced it with a Horstmann (this being the only one I could get quickly).

Unfortunately the radiators are red hot but I now don't have any hot water.
I noticed the A & B Port on the Honeywell valve and put the new valve the same way, but will they be the same?? as the B port (C/H side) is red hot and the A port (Hot Water side) is cold leading into the tank even when the water only is selected and the heating is turned off.

Can the valve be the wrong way around or is it another problem????

 

[waterworks]

You should have instructions with your new 3 port valve showing which port goes to heating and which port goes to hot water and that is how you should have fitted it even if they are marked different from the Honewell valve.

 

[ChrisR]

B is for Bath!!
Wrong way round.

 

[D_Hailsham]

The valve is the wrong way round!

A port is the Radiators; B port the Hot water.

See Horstmann 3 port valves

This is the same as Honeywell, Drayton and most other valves.

 

[darrenj]

Thanks very much for the quick replies.
The instructions that came with the valve were not clear and not like the one you attached for me D Hailsham, thanks, that makes it very clear.

I obviously will not make the mistake again of thinking it is an industry standard that 'A' always goes the same way and 'B' always goes the same way.

Thanks again, maybe I will sleep tonight not thinking about it, I will let you all know if it works.

 

[D_Hailsham]

I obviously will not make the mistake again of thinking it is an industry standard that 'A' always goes the same way and 'B' always goes the same way.

But Horstmann and Honeywell do use the same identifiers: A = Radiators, B= Hot Water (or Bath as ChrisR put it). If you put the new valve in the same way round as the old one, it means the old one was also the wrong way round!

Might be a good idea to check the wiring. Here is a diagram which should help:

 

[darrenj]

Thats worrying. I have lived in the house for 7 years and never had the motorised valve replaced, but I have never had a problem with the water/heating before.

The hot water side of the motorised valve connects into a 22mm pipe going into the hot water tank and the heating side connects to a 22mm pipe going down and under the floorboards, I take it that is correct?, if so then you are correct the valve has been fitted wrongly as the Honeywell valve definitely had 'A' pointing towards the tank as I wrote it on the pipe before disconnecting the valve to remind me when fitting the new one.

D Hailsham, I cannot open your wiring diagram, any chance of resending so I can have a look to see if it correct.

Thanks

 

[D_Hailsham]

I once came across a DIY site which gave completely wrong instructions as to how a midposition valve should be installed. The person who did yours probably wrote it or referred to it.

Here is the wiring diagram from the DIYnot site:
(Click the image to open a larger copy or right click to save a copy)

View media item 70

 

[darrenj]

Thanks for the diagram I will check it out.

I know everything tells me it is the wrong way, and the instructions sent prove this but would the old valve have worked for over 7 years if it was the wrong way round???

 

[D_Hailsham]

would the old valve have worked for over 7 years if it was the wrong way round???

That is a mystery, maybe A and B on the old Horstmann valve meant different things or the wiring colors were different.
If you have the old valve still, what is the model number? Also check which port is open The B port should be open as the "stopper" is held against the A port by a spring.

 

[darrenj]

The Honeywell valve removed is model number V4073A1039-7, the new valve fitted is a Horstmann F322m

I will check the wiring because I (probably wrongly again) assumed that as the wires are the same colours that they would go in the same place!!!!!

 

[D_Hailsham]

The Honeywell valve removed is model number V4073A1039-7, the new valve fitted is a Horstmann F322m

My mistake! I was thinking you replaced a Horstmann with a Honeywell

It appears you are not alone! I have just come across a post on another DIY site with exactly the same problem! Sounds as if there could be something wrong with the Horstmann Valve. It's at Faulty Heating system

I suggest you give Horstmann a phone on 0117 978 8700 and explain your problem.

 

[darrenj]

Thanks for your help on this.

I will change the valve around tonight and check the wiring so I know how it should work, and it is at the recommended standard, if it doesn't work after that I will contact Horstmann on the number you give.

I will let you know how it all goes, this may help if anyone else has a problem in the future.

Thanks

 

[darrenj]

The system all works fine now.

I changed the valve around last night and checked the wiring, the blue wire was going into connector 1 rather then 2 (not sure if this made any difference) so I changed this as per the diagram D Hailsham gave me and moved the valve.

Thanks very much for all the advise it certainly was spot on.

 

[D_Hailsham]

the blue wire was going into connector 1 rather then 2 (not sure if this made any difference) so I changed this as per the diagram

The blue wire is the Neutral for the valve motor and should go to the neutral terminal. You can usually identify this quite easily as all the wires to the terminal will be blue.