Boilermate 2000. No hot water.

8 Jul 2013
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United Kingdom

I posted this a few minutes ago under the subject "No pilot light" when I thought my problem was with my boiler. Now it appears to be down to my Boilermate 2000.

My actual problem has always been no hot water. I thought it was because of the boiler, but that now appears to be working again.

I've taken the front off the Boilermate 2000, and the correct combination of LEDs light up when I switch the heating on, and I can feel one of the pumps working, which is good.

But when I open a hot tap, LED bar 3 (signifying "Heating pump on") should light up ( but it doesn't) and the domestic hot water pump should run (it doesn't appear to). I'm not sure which of the 3 pumps should be working (the one connected to "primary return (to boiler)", the one connected to "Central heating flow", or the one connected to "Drain"). It is the "Central heating flow" one which vibrates when I turn on the heating. Confusingly (to me) the pipe labelled "Hot supply to taps" does not appear to have a pump connected.

So, does this look like I need a new hot water pump? And if so, which of the three pumps mentioned above is the one that needs replacing?

This all started because I decided to see what would happen if I turned off the mains switch to my Boilermate 2000. That was a silly thing to do in hindsight... I had plenty of hot water until I did that...

Again, any advice will be greatly appreciated!

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The boiler heats the boilermate. The heat in the boilermate is pushed to the radiators when ch is selected on the programmer. When boilermate reaches temperature, boiler and its pump shut down.

When you run a hot tap, cold water flows through a coil in the cylinder, coming out hot to be blended before coming out if the taps. If the boilermate has external heat exchanger, then water in the cylinder would be pumped into the external heat exchanger (which would have been a coil in th example above) to heat cold water for hot taps
Ah I see, thanks. So a pump needs to work to pump some hot water into a cylinder to heat the cold water for the taps?

Well, this morning, I turned on the hot tap, and the correct LED lit up to show that the hot water is on, but no pump appeared to be working. I had hot water for a few seconds before it started to run cold again.

So I guess it sounds like a pump needs replacing? Which pump would that be? the one on the "Primary return to boiler" pipe? Is there anything I can try before calling out a plumber? It's on setting 3 (max). The pump on the "Drain" pipe is on setting 2. I've tried that on setting 3 but still no hot water.

Thanks again

The pump on the RHS is the DHW pump. Thats the one next to the plate heat exchanger. Check the pump when a hot tap is opened, it should run and be set on max. If it doesn't run, check for power to the pump, and check that the pump is free to rotate, by removing the large centre screw and engaging the impeller with a narrow screwdriver.
Your boiler stat should be set to max.
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You really need some diagnostic work rather than blindly changing pumps.

For example does a pump have a supply to it!

Even many engineers don't like working on these!

Bet its a sensor.

Gledhill technical may help you with a diagnosis as these PCBs will self diagnose if you press the orrect sequence of buttons.
These tanks are terrible. The best thing you could do is fit an unvented cylinder.

But as said above, you can't guess with these over a forum. You need some proper diagnostics.
These tanks are lovely!

But you do have to take a little while to understand them.

Because many of the sensors are low consumption three wire digital they cannot be easily tested in situ. ( Or at all for most engineers except by substitution! ).

Replacing with an unvented is a common response from those who dont understand how to repair these units!

Replacing with an unvented is a common response from those who dont understand how to repair these units!


Don't get me wrong I repair these as and when they come in.

Let me rephrase my original response 'in an ideal world were money grew on trees people would replace these'

Not because I can't repair them but simply because they far too OTT and costly for what they basically are.
Hi all,

If no error code on the LCD screen. Change both sensors if DHW failing GT153 part number, both have long white cables on. Or get a suitably qualified guy out to do this....
I am still waiting for someone to give me an explanation why anyone would fit one of these in preference to an unvented.


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