Hot water, low pressure, combi system

[Cableguy]

Hi guys,

I was wondering if you can help me with the problem I am having at the moment.

Basicly for the past few days, the hot water line, has significantly dropped pressure. No matter which tap i use, kitchen, bathroom or shower.
When you first turn on the tap, there is good pressure, then after a few seconds it slows right down.
It had been great, previously, always same pressure as the cold tap, but now it's terrible.

The system is a combi system. I tried switching off the combi to see if it made a difference to the pressure but it made no difference.

If I have one hot water tap open, no hot water comes out any of the others.

I have searched hi and low, but no answer or solution.

If anyone can point me in the right direction, I'd be very greatful.

 

[ShaunCorbs]

and all your other cold taps are great / no reduced pressure?

any work been going on?

 

[Cableguy]

and all your other cold taps are great / no reduced pressure?

any work been going on?

Yes that's correct, all cold water taps are fine and no works have been carried out. I thought maybe some kind of airlock, but I don't think ita possible with a combi system.

 

[Riley]

Won't be an air lock what's the boiler make

 

[Scott_D]

Any water main work recently in your local area?

 

[Cableguy]

Any water main work recently in your local area?

Boiler make is Glow worm, betacom 24c.

There has been no water works in the area.

 

[Riley]

I'd be looking at blockage in boiler. That being the case you'll need a gs engineer

 

[Cableguy]

Hi Guys, an update on this.

Before I called a plumber, I thought Id do a few checks to try to narrow down the problem area.
I switched off the boiler, disconnected the cold water supply, and the DHW from the boiler. Then using a flexi pipe, connected the CWS direct to the Hot water pipe, feeding the entire house. (by-passing the boiler)
I was trying to see if there was a blockage in the pipes running through the house or not.
Turned on the CWS at full pressure, and opened the hot water taps, one bay one, in kitchen, bathroom and the shower. Some black and brown crap came out for a few seconds, but the pressure was very good. Rate of 15 liters per minute. same as the cold water taps. left it running for about 10/15 minutes.
This eliminated the chance of a blockage in the house pipes.

It means something is either clogged in the boiler or preventing it from flowing properly.

I connected the CWS back to the boiler and left the DHW pipe disconnected. placed a bucket under the outflow pipe under the boiler and opened the CWS fully, allowing the water run though the boiler at full pressure. as the water came out of the boiler and into the bucket, was very low. At a rate of approximately 5 liters per minute.

I decided to reverse the flow through the boiler (not sure if its a good idea, but anyhow).

Connected the CWS direct to the output of the DHW supply. this means the water was running through the boiler and coming out of where cold water would usually be going in to the boiler.

I was expecting the water pressure to be as low as before, but water running in reverse through the boiler was at full pressure of 15 liters per minute.

So im confused to why would the water flowing the correct way would have such a low pressure, 3 times less than it was going in, but when the water is flowing in reverse wouldnt have a drop in pressure.

if this makes sense, any one has any ideas?

Thanks in advance.

 

[Dotty]

You need a gsr as advised by Riley in post #7.

Stop messing around with it yourself.