Main Medway Super

Joined
23 Jul 2010
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Location
Essex
Country
United Kingdom
We are having trouble with our Main Medway Super, this has been serviced throught its long life.
The problem is that we are now getting very hot water, and cannot control it to use our shower. which now runs very hot and then cold (without using the cold supply).
A Service engineer has had a look and decided that it is the diaphram, and said he could replace it.
However, he is saying that his supplier is having problems getting the parts.
This is over two weeks ago.
Is this about right?

Thanks
 
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i don't think a diaphram will sort the hot water to run so hot, if the diaphram had gone it wouldn't be able to push the gas valve open to fire the multipoint up, am just wondering if its over gased or the heat exchanger is scaled up making the water heat up quicker, in my opinion id be recommending a replacement as there only around 250 quid for a new 1. but the parts are normaly on the shelf if not next day delivery !
 
Thanks crashndie,
I was told that these type of mutipoint boilers cannot be installed any more, or have I been mis-nformed?
When the engineer inspected the boiler he increased the flow of water to reduce the temperature, so that we could shower o.k. until the new diaphram arrived.
When we use the shower, when we turn on the hot tap the water runs at a normal temp for a few minutes, and then gets over hot.
when we compensate that by turning on the cold tap, thats o.k. for another minute or so, and then the hot tap runs cold til we turn it off and then start again?
 
I wouldn't rule out the diaphragm, I've found that over the years, as the diaphragm stretches, the flow rate is gradually reduced to the point where it eventually wont even work.......I'd be changing the diaphragm then see what happens.
 
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I think that I have realised whats wrong and why what you are doing is causing problems.

These effectively control the temperature by INCREASING the flow of water through them. Now we are in summer the water is coming in quite warm.

When you turn on a cold tap that reduces the pressure and thence the flow through the hot getting it hotter still.

Can you increase the HOT flow only? Usually there would be an adjustment in the heater.

You may need to unblock the holes in the shower head with a pin etc?

Tony
 
Thank you all for your help,
I have changed the shower head and will wait until my wife has her shower (who wants 3rd degree burns?), and see if she notices any change..

t.a.
 
Whats the water like at a ordinary tap ? a shower problem may be more to do with a shower fault as opposed to the water heater.

If you dont have a problem with the hot taps, I would suspect a problem with the shower itself, possibly slightly blocked filter on the cold inlet and not the hot causing an imbalance. if its a thermostatic maybe cartrigde is faulty and not regulating the temperature.

I would not be looking at a diaphram fault if your water is too hot !

Is the flow rate good from the water heater, if its too slow this can cause excessive temperatures.
 
Why not just run the shower and just put your hand in it?

Or better still a thermometer if you wanted to do it scientifically.

Tony
 
just reread your post does the temp fluctuate when just using the taps ?

If not must be the shower !

If it does, does the water heater go out and you have to relight it ?

If thats the case its overheating and should be a simple fix.

Very easy to fit a new one if its a really pricey repair.
 
Why not just run the shower and just put your hand in it?

Or better still a thermometer if you wanted to do it scientifically.

Tony

But an easier way that nurses and mothers use is their elbow !
Pelchy thinks thats better than a thermometer !
 
Now that it has been mentioned, the problem with the very hot water did seem to start around the beginning of the warmer weather, i.e. when the cold water temp changed.

The temp. at the sink taps now seem pretty constant, it wasn't until the engineer made adjustments!

Also, I have put on a "new" shower head (I mean, everyone has a spare one of thse don't they?), and I must say that we have had the best shower for weeks!

It was a joke when I mentioned I would wait for my wife to have a shower so that I would not get burnt............sorry!
She does not like hot showers as such, the water has to be tepid, so if she can adjust taps that critically then things are o.k.

As for waiting for two weeks for a new diaphram, I have told the engineer concerned that I will look elswhere, I have not heard from him since! am I being unreasonable?

I'm going to give it a few days to see how things go.

I'd like to thank all of you for taking the time to give free advice and opinions, and I will come back and update.

thanks again.
 
We dont think that you need a new diaphragm at all.

Your fellow probably doesn't either but rather than lose face he told you something ( or just wanted to charge you for something! ).

Tony
 
Thought I would report back after all of your help.

When the engineer called in early July, and adjusted the flow of the hot water to run faster, the temperature stays constant, but he left saying that it was the diaphram, and he would replace it.
After waiting for over two weeks, despite me contacting him. I told him we would look elswhere. and have not heard from him since.

After changing the shower head from a 5" to a 2 1/2" as suggest here, we have a very good shower and the water stays constant throughout the house.

We are now waiting for another engineer to call in the near future.

thanks again.
 
I dont understand why you want another engineer.

In any case engineers dont just casually call when they are passing. If you had any problem then you call them and they usually come the same day at this time of year.

Tony
 
He was not "just passing" he was visiting a neighbour by arrangement to do their annual service, the same as he has been doing ours for over 20 years, we were expecting him to call at some time, he knew we had a problem, because I had spoke to him previously.

Whilst here he mentioned that he had moved out of our area.
He told us that he would get a new diaphram and come back.
He did not contact us for about four days, our cupboards were still empty, the doors removed and the shelves taken out for access, when I contacted him, he said he would ring me back same day, from then on I could not contact him at all, just leaving messages (polite) on his answer phone.

As a last resort, on a Wednesday, after trying to phone him again from our land line, and getting the same message, I rang him again at once, from my mobile (he did not know that number), and he answered at once. he said he was on his way to see if the part was in, and he would ring me straight back, I said that if we had not heard from him by the end of the week, I would look elswhere. I have not heard from him since.

Do you think I was patient enough to get a new diaphram for this boiler? the guy obviously did not want to come back because he had moved.
I have not a problem with that, all I ask for is a straight answer.
 

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