Megaflow E7 - hot water wont come out!!

[groganpaul]

Hi guys,

I've got a very odd problem with my Economy 7 Megaflow boiler.

Turned the hot tap on and hot water came out for a minute or two then it went luke warm then it went virtually cold.

I asked my Dad and he said its probably the cold water combination valve has failed or is full of gunk.

I decided to replace the combination valve.

I turned off the mains water and opended the hot taps in bathroom and kitchen and LOTS of hot came out???

So the tank was indeed full of hot water but for some reason it wouldnt come out.

I changed the valve and turned the mains water back on. I ran the hot tap for a minute or two and all seemed well - hot water again.....although I didnt quite understand how there would still be hot water left in the tank after I drained it down?

My misssus just went for a shower and its now running cold again (even after I tried turning on the boost for thirty mintues)

Its as if there is hot water in the tank but for some reason the cold water comes out and the hot water stays trapped inside the tank.....I'm stumped!

 

[Agile]

Well I cannot guess what you are doing!

Can you post a picture of your cylinder? Serious work on an unvented should be by a qualified person.

If its never been serviced the filter could be blocked or the PRV may be jammed.

Have you touched any valves or done anything to the pipework or anything else in the house, WMC etc?

Tony

 

[groganpaul]

My Megaflow is indentical to this one - //www.diynot.com/forums/viewtopic.php?t=201568

two thermostats (top one for immersion, bottom one for E7)

Its all electric.

Cant get a piccy as I'm staying at my brothers house so my missus can get a shower in the morning.

I havent touched any valves or added anything to the sytem. One day its working fine, the next its not!

I did try to renegerise the tank (followed the instructions on the tank) but that didnt make a difference. The PRV seems to be fine. It worked properly when I was following the instructions.

 

[twgas]

I havent touched any valves or added anything to the sytem. One day its working fine, the next its not!

In your first post you said you changed the (conbination)valve, now you say you never changed any valves.

Your problem(s), I think, is the cold is not balanced and the shower is passing from cold to hot.

 

[groganpaul]

Mick,

Besides the valve I changed I didnt touch or alter any valves. I thought I made this clear by explaining I had changed the combination valve in my first post?

I was replying to Agile's post asking if I had changed anything else. I did not.

As it happens, you were spot on!

I phoned my Dad and he came and had a look at it. He came to the same conclusion so I bought a new shower mixer tap.

Problem solved [/b]