Myson Apollo boiler: Loss of hot water

Kav69 · 20 Nov 2008

Hi folks,

I've got Myson Apollo cabinet boiler (System Boiler) and recently I loose hot water after about 5min in the shower. I have been told that this might be due to faulty 'Dip Tube' but I'm not sure where this might be! On the boiler or the tank?
I have got a little space above the boiler to the ceiling and would be very awkward to replace it if it's there. Does this mean that I have to remove the boiler from the mount on the wall?
Does anybody have diagram of this boiler?
Suggestions greatly appreciated.

Regards

Kav

gas4you · 20 Nov 2008

If your ch works ok, then I would think the boiler is ok and the fault will lie with the external HW controls (zone valve if you have one) or your HW cylinder so badly scaled that you do not get a full tank of hot water.

Kav69 · 21 Nov 2008

Dave,

Thanks for the reply.
I almost didn't understand a thing

What is 'CH' and where I can find external HW controls (or zone valve).
I had a look at the tank but as you would have expected didn't see much after removing the top lid (so now you would guess what an expert I am in this

)
So would you explain this in a way that I may understand.

Regards

Kav

D_Hailsham · 21 Nov 2008

CH = Central Heating
HW = Hot Water

Kav69 said:
I have been told that this might be due to faulty 'Dip Tube'

Who told you this? You do not have a dip tube on your boiler.

Where is your pump?

Do you have either of these valves anywhere; e.g. near the HW cylinder?
View media item 5945 View media item 5946

Kav69 · 22 Nov 2008

Hello and thanks for your reply.

I didn't find anything like it on the system. However, I've taken a few photos of my system. Hopefully you can say which is which because I can't!

Many thanks

Kav

twgas · 22 Nov 2008

doesnt look like your tank will last many years due to leaks, but aside from that there should be a cover on the immersion - when its switched on it will have exposed mains voltage (dangerous), however if the tank is hot the chances are its the blending valve.

D_Hailsham · 22 Nov 2008

The two large red things are pumps. The one in the left picture is for the hot water and the rectangular white box to the left is the HW thermostat, which should be set to 60°C. The pump in the right picture is, I think, for the CH (central heating, remember

). When the hot water is being heated the pump in the left picture will run. Turn the HW ON at your timer and turn the HW thermostat down to lowest; the pump should be silent. Now turn the HW thermostat up to max and you should hear the pump running (put the handle of a screwdriver against your ear and the other end onto the pump and you will hear it clearly). The pump has three speed settings - switch on the side - so try all three speeds, in case one speed is faulty. If it is, you will need a new pump.

If you can't hear the pump working it may be jammed. Turn the HW stat right down and remove the large screw in the centre of the pump. You will get a little water coming out, so a rag etc is helpful. Inside the pump you will see the end of the shaft with a screwdriver slot. Using a screwdriver try turning the shaft. It should not be difficult to turn. If the shaft is easy to turn, turn the HW thermostat up to max and watch the shaft - you should be able to see it turning (use a torch if necessary). Replace the large screw in the end of the pump.

If the pump does not turn there is an electrical fault, either inside the pump or there is no power getting to the pump.

PS you will not have any motorized valves as separate pumps do the same job.

Kav69 · 22 Nov 2008

Hi Mike,

The Immersion is dead and cut from the main so sholdnt' be any danger.
Which one is "Blending Vave"? (tank is hot)

Thanks

Kav

twgas · 22 Nov 2008

this is the blending valve

turning the knob on top may solve your problem, unless the internals are broken.

HW thermostat, which should be set to 60°C.

as its a thermal store I would recommend 75-80

Kav69 · 22 Nov 2008

Guys,

Thanks very much for taking your time to resolve my problem.
Firstly, I have learnt one if not two things: CH stands for Central Heating

.
Secondly, I tested both pumps and they work just fine (at least I'm not to replace a pump - maybe something more expensive though

).
I opened and closed the "Blending Valve" to the ends, result? well, when it's closed, lots of COLD water and when it's fully opened maybe slightly more hot water but still is not even close to what it was before.
I have been in this house for about 5 years and haven't touched anything in the CH and/or HW system and this just happened over night.
At first I though maybe it's something to do with the CH but I tried the shower with CH off and no difference.
A question about the BV (stands for Blending Valve

), when it is fully opened, should it not just let the hot water go through and not cold water? because if this is the case, the valve should be faulty as you can feel the cold water running through the pipe towards the valve (the pipe get very cold).

Regards

Kav

twgas · 22 Nov 2008

tap water would be very hot if BV turned to max - technically you dont open and close it - when it's turned one way the cold opens and hot closes, turn other way opposite happens, well more or less

twgas · 22 Nov 2008

tap water would be very hot if BV turned to max - technically you dont open and close it - when it's turned one way the cold opens and hot closes, turn other way opposite happens, well more or less.

yes, it does sound faulty.

Kav69 · 22 Nov 2008

Mick,

Would the problem lies in the VB. Because when it is turned (technically speaking

) to the Max there is very hot water running from the tap but just for a few seconds and then it starts getting colder and colder till it gets to a certain temp and stays like that.
As I've said when the VB is set to Max, you can still feel the cold water running through the pipe (to the valve) which may not the way it meant to be (maybe a little)!?

Cheers

Kav

twgas · 23 Nov 2008

Is the tank still hot when the tap water is not?

Kav69 · 23 Nov 2008

It's not really easy to say if the temp changes in the tank because of the isolationa etc. but I would say if there is any changes, that will be very little.

Kav

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Myson Apollo boiler: Loss of hot water

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