Gledhill Boilermate 2000 & The ever increasing cost of gas/electricity

hdsn555

We live in a detached 2001 house, with a Gledhill Boilermate 2000 with a Potterton Suprima boiler in the Kitchen. I'm extremely conscious of how hot our airing cupboard is, and the frequency of how often the boiler kicks in to top up the temperature of the water in the boiler mate.

Given the runaway prices of gas and electricity, I'm looking to understand if it's worth ripping the damn thing out and getting a combi boiler.

Whilst we were away in early July, we used between 4.5 and 7.5 kwh of Gas, without anyone being home. This was purely driven by the boiler kicking in to maintain the water temp in the boilermate, without anyone actually using it. Its my understanding this system is designed to be always on, but given how wasteful (an potentially expensive) this now is I'm just not sure.

Another sore point is sadly the EPG report says we have cavity wall insulation, but having had a bores cope report done, it's clear we have empty cavities. So as soon as the heating switches off we notice the temperature plummets quite quickly.

Has anyone else had any experience with these? I've tried to search around but posts are pretty old.

FreeBear

Two things you can do - Turn the thermostat down on the tank to 50-55°C. Turn the boiler off when you don't need hot water (e.g. going away).

I have my HW thermostat set to 52°C, and only fire the boiler up an hour or so before I want/need a bath (maybe once a week), and use a kettle or electric shower for the rest of my hot water needs.

As for further savings - Get yourself a programmable room thermostat that allows for different temperatures throughout the course of the day. This will allow you to set the heating to (for example) 18°C in the morning, 20°C in an evening, and 15°C at night. Will save you quite a bit of money over having the heating on at 21°C all day/night.

sk2402005

7.5Kw is quite low, only around 60p.

What i can’t find is an efficiency rating as it’s a thermal store system, but it is a conventional boiler doing the heating, and i would expect around 80% efficiency.

Unless its proving unreliable, i would keep it, as upgrading to a new 90+% efficiency boiler will only save you maybe £100 a year depending on your gas usage.

Also i wouldn’t advise turning down the thermostat for the water as recommended above, it needs to be 65'C to kill legionaries bacteria.

Loft insulation is quite cheap, and cavity is probably well worth doing.

Another reasonably cheap upgrade is thermostatic radiator valves, and as recommended by Freebear a smart or programmable thermostat is a good idea.

ComicGeek

I ripped our boilermate out when we moved in 12 years ago, absolutely horrible things.

The store is kept at a high temperature, from which the radiators are fed directly. The hot water for showers/sinks is then generated instantaneously via a heat exchanger, so is less of an issue with legionella with lower temperature. Essentially the opposite to a standard cylinder where the stored water is fed directly to the showers/sinks.

A combi boiler would be much more efficient if that meets your hot water needs (ie maximum possible hot water flow rate), but probably worth waiting until you need to replace the boiler rather than rushing to do it early. 

RedFraggle

Have you got the boiler temp set to max? As counterintuitive as that sounds that's when the combined system runs most efficiently. 
If the boiler isn't it will kick in constantly as it can't get the thermal store up to temperature. 

RedFraggle

Remembered 2 other things that were wrong with the one in our flat....
1. Is there water in the reservoir at the top? There should be a cover on this to minimise evaporation but if it's missing a dinner plate does a good job.
2. Has some numbskull pulled out the thermostat cable to the thermal store not knowing what it was. 
There are a few specialist engineers. I have details for one that covers London if needed. 

FreeBear

sk2402005 said: Also i wouldn’t advise turning down the thermostat for the water as recommended above, it needs to be 65'C to kill legionaries bacteria.

No. It. Does. Not.

Anything over 60°C will kill the bacteria instantly. Between 50°C and 60°C, the bacteria will still die, it just takes a little longer. However, Legionella is only a (small) risk if you have an open tank where the water is around 25°C to 45°C. The Gledhill Boilermate heats incoming cold water from the mains, not a cold water tank, so the risk of Legionella is zero as the water will have been treated by the water company.

As for the risk of contracting Legionella - There are about 200-250 cases reported annually. Of those, approximately half of them are contracted overseas. You are currently more likely to contract Monkeypox.

Bendy_House

On the basis alone that the Gledhill heats the DHW 'instantly' from fresh incoming mains water, much like a combi boiler, the risk must be infinitesimal.

I presume the Gledhill's STORED water is 'system', so sealed and treated? In any event, the 'stored' won't be making contact with the DHW.

Section62

Bendy_House said:

I presume the Gledhill's STORED water is 'system', so sealed and treated? In any event, the 'stored' won't be making contact with the DHW.

I've never seen one in real life, but I understood they were open vented.  It was a selling point that they didn't need a G3 qualification.

Maybe there are differences between models.

Bendy_House

Section62 said:

I've never seen one in real life, but I understood they were open vented.  It was a selling point that they didn't need a G3 qualification.

Maybe there are differences between models.

Oops - I just assumed. So unlike me...

Either way, tho', the stored water is presumably still completely isolated from the DHW, and will have inhibitor and stuff in it? It's the same water that goes through the boiler and rads?

RedFraggle

http://www.gasapplianceguide.co.uk/Gledhill Boilermate explained.htm