Hot water from taps for about 2 mins then lukewarm, Central heating works fine.

Hello everybody,

I have a boilermate 2 .
As the title of my post says I get hot water from the taps for about 2 minutes and then it runs cold. The central heating works fine.
I have looked in the expansion tank and there is water in the system.

After reading similar posts in this forum am I right in saying that the cause is a blocked mixer valve or does the system need a descale ???
I have tried to turn the mixer valve and it feels seized.

Any suggestions / pointers would be greatly appreciated.

Rgds.

Silver

How old is the unit?
How much DHW use has it had?
Hard water area?
Sounds like mixer valve if seized.
But if the other question are;
8 years plus
Family use
Hard water area
Then descale needed.
Try mixer / blending valve 1st if cost an issue.
Mike
MGC/H2O
Norwich

Oh and check cold feed to unit not blocked.
As the unit may not be 100% full.
Mike

Thanks for the quick reply Mike.

The unit is over 10 years old, so I'm going to take your advice
change the mixer valve and have a look at the cold feed supply for blockages whilst I've got the mixer valve out.

I will give it a descale whilst I am at it, so...

What is the most effective way of descaling the boilermate and is there a particular descaler that you would recommend ?

Rgds.

Silver

You need a machine to descale the unit.
Would not recommend the normal power flushing pump / unit.
I use one designed for the job.
Mike

Mike,

Thanks for the information.

I will change the mixer valve and depending on the result, get a descale done by a plumber,

Thanks again,

Silver

I have the same problem, woke up this morning with only a minutes worth of hot water but the CH is fine. The Boilermater II is requesting more hot from the boiler when the hot tap is turned, and the boiler is firing. Also the F&E tank is full. We live in a "slightly hard" water area and I was just about to clean the system with some sentinel this winter as it hasn't been done since we moved in (6yrs ago), the system is about 15 yrs old.

• The Brawa-Mix I have found online is £110, which seems like a lot to spend on an off chance. Can someone please confirm if this is what I need to do, or if there is any way to double check mine is faulty?
  

Also:

• Is it as easy to replace as turn off the water and swap it out?
  

• Is the cold feed supply that must be checked for blockages the pipe running along the bottom, and do I just poke something in to check?
  

Did the problem develop slowly or was the HW fine one day then gone the next?

IF the former then you need a descale, if the latter then it's the mixer valve.

Mike

Thanks, prompt as usual. I've ordered the part so hopefully it won't be long until we can again use the shower!

Just wanted to let say thanks again for the advice! fixed the problem over the weekend.