Powermax 155 Blending Valve

[christiansearle]

Hi

First post and first time on the site, so please bear with me.

I have lived in my house for about 4 years and had terrible hot water. I will get about 30 seconds of it then cold. I have a powermax 155 boiler.
I have been reading and only thing I can find which is causing the lack of hot water is the blending valve. I have ordered one and cost about £88.

Can anyone tell me how long it would take to replace the part and roughly how much it would cost ?

I live in Rainham, Kent.

I hope this works as the mrs is wanting a bath !!

Thanks
Christian

 

[Stingray13]

Christian,

Your deffinetly have the 155 not the 155x?

when running your tap find the blending valve and feel all 3 ports on it, you should have one hot, one cold and one medium. like the 3 little bears. if you don't have the medium one after 30 secs spot on if not come back to us

 

[christiansearle]

Hi Stingray

My boiler definatley says 1500, cant see any X im afraid.

I had British Gas cover for years and I had 4/5 engineers come out and all said we dont touch them boilers. Or you need a new boiler.
Sorry,.. but idiots.

My blending valve is hot on all 3 points at present. May be as my CH is on ? Im sorry but I dont have much idea's when it comes to plumping.

Thanks Christian

 

[kevindgas]

I had British Gas cover for years and I had 4/5 engineers come out and all said we dont touch them boilers. Or you need a new boiler.
Sorry,.. but idiots.

unfortunately they are only doing what a lot of sensible engineers would do and that is saying sorry don't know enough to work on your boiler

these are different to most other units

so hopefully i can help you as i have a reasonable understanding of these beasts!

the mixing valve takes about 3/4 hour to replace but is normally on replaced if it is leaking badly (most do!) turn the cold water off first the turn on a hot tap to relieve pressure have a couple of towels as there will be some water in the valve

if it is OK then all you need to do is adjust it - on the valve head you will see + - symbols and the valve is situated about 9 -10 inches down from the top of the unit generally on the right side

with the store hot - run a tap and as other post says 1 side (the cold inlet) should go cold the 2nd (the outlet from the store) should be too hot to keep your finger on for any time and the 3rd side (the outlet to your hot taps) should be be hot but not so hot as no 2
adjusting the head increases or decreases the temperature of 3 by mixing 1&2

hope that explains it

 

[christiansearle]

Hi Kevindgas

I am not a plumber but could I do this myself ? Replace the blending valve ?

I know what you mean they are a beast. Huge bl00dy things.

Ive taken the cover off and can see the valve half way down on the right hand side. Black head with 3 way pipe outlet (if that makes sense).

So you think may be all I need to do is adjust the head ? The "head" bobbles a bit, so can I turn it ?

Thanks Kevindgas for replying.

 

[kevindgas]

yes you can adjust it - sometimes they stick so you think they dont move !

easy enough to change if you reasonably competant at plumbing joint compound on the threads is a good idea and only tighten up enough to be watertight don't overtighten!

on some of the valves you can take the plastic head off by removing the screw allowing you to use an adjustable to free up the valve it just rotates like a radiator valve

 

[christiansearle]

Hi Kevindgas

Thanks for your help, much appreciated.

This may sound stupid, if I undo the the 3 nuts at each end so I can take the valve off will no water come out anywhere ?
Sorry if sounds stupid. Shall I turn the boiler off and the water at the mains ?

I will see if the head comes off first before I attempt to undo the nuts.

So would you suggest I give it a go before replacing it and getting in a pluber then ?

 

[kevindgas]

This may sound stupid, if I undo the the 3 nuts at each end so I can take the valve off will no water come out anywhere ?
Sorry if sounds stupid. Shall I turn the boiler off and the water at the mains ?

quote]
water will pour out if you havent shut off the cold water supply to the valve usually there is a stop cock fitted on the cold supply (no 1 Pipe) before the valve if not you can turn off all the house at the stopcock where the supply comes into the house (under the kitchen sink or in the meter housing outside usually)

as i said turn off supply , open a hot tap to relieve pressure water should stop flowing in a few seconds
then you can undo the 3 nuts but a small amount of water will still be present so towels needed to catch it

you don't need to turn boiler off as the water only passes through a coil and so the tank won't drain

 

[christiansearle]

Thanks Kevindgas

Yes thats right, I will turn the water off at the mains which is under my sink.

Sorry and thanks for all your replies, so I will :

1) turn off water at the mains (stop cock)
2) undo the nuts and take the blending valve off and give it a clean as I have read that normally covered in limescale.
3) adjust the head to increase and decrease the temp.
4) put the valve back on and test.

I have got a new valve awaiting for pick up, I will try this first before I pick it up but the valve is at least 4 years old, since ive been in my house at lease. never had hot water in that time !

Cheers again Kevin

 

[kevindgas]

never had hot water in that time !

Cheers

sounds about right

 

[christiansearle]

Hi again

I have just touched the 3 outlet pipes.
All 3 pipes are really hot. I run the hot water tap in the bathroom for about 30 seconds.
I have now touched the pipes again.
The pipe coming down is still really hot but the pipe going down and the pipe going right is cold.

I have used a screw driver and moved the + and - sign and hasnt done anything to the temp.

Should I now take the blending valve off and clean etc and put back on or shall I just pick up the brand new one and replace it ?

Thanks

 

[nicknox]

Remove the existing valve and on the hot water outlet from the cylinder to the top of the blending valve is a small mesh filter. These have a tendency to scale up causing limited flow through the valve leading to poor hot water.
Try that and save youself some money

 

[christiansearle]

Thanks nicknox, I will try that.
Any suggestions what to clean the valve with ? Someone at work suggested DS3 is it ? Sulphamic Acid.

Thanks

 

[kevindgas]

I have used a screw driver and moved the + and - sign and hasnt done anything to the temp.
Thanks

you have moved the screw ! what about the brass valve spindle underneath? if you have adjusted that then the valve is KN***ered

by all means clean the mesh any scale agent should shift it but i'm not 100% convinced this would cause the problem desribed. happy to learn thou if there is something i'm not getting

 

[audisport]

Hi

First post and first time on the site, so please bear with me.

I have lived in my house for about 4 years and had terrible hot water. I will get about 30 seconds of it then cold. I have a powermax 155 boiler.
I have been reading and only thing I can find which is causing the lack of hot water is the blending valve. I have ordered one and cost about £88.

Can anyone tell me how long it would take to replace the part and roughly how much it would cost ?

I live in Rainham, Kent.

I hope this works as the mrs is wanting a bath !!

Thanks
Christian

Hi
You will more lightly find the coil is scaled up and will need to be descaled. As the thermal store hot water heats your hot water supply this is the fastest way to make scale which the powermax does very well. when you are descaling the coil you can put the old mixer valve in the ds3 to clean it. If you have the later 155 you will have a heat exchanger which you can't descale and only replace