Gledhill Thermal Store - I thought it was economical!

[matg]

Hi all,

We moved house in late October from a property with a MegaFlow and Combi boiler, bills were for it were good, during the winter we kept it on 24/7 using a Heatmiser digital thermostat to control the temperature.

Our new property has a Gledhill Thermal Store unit and a Pottern boiler installed when the house was built about 8 years ago. We just got our bill from November to early Feb whoa! I thought thermal stores were economical but our bill is huge and we have not been leaving it 24/7 partly as the boiler and the pump are quite loud.

I'm after some tips on how to keep the bills down.

The boiler is set to come on about 7am and go off about 8:30am and then again at around 4:30pm and off about 10:30 pm, thermostat is at 21 degrees C

With this system as I understand it though out of these times the boiler can come on to heat the water in the tank, this seems to happen quite regularly and even in the middle of the night. The water is also heated to a very very high temperature and then using a valve on the cylinder you mix it with cold water so you don't burn yourself when using the taps. But to me this does not make sense, I'm paying to heat water up to then mix it with cold water to cool it down

Also the Summer/Winter gauge on the front does not seem to affect the temperature of the water but the amount that is heated up. For example while its in the Winter red area we get enough hot water to half fill a bath but when in the Summer blue section we only get a couple of inches of hot water - is this correct??

And finally (sorry this is so long!) we get a annoying buzzing coming from the cylinder at random times every couple of days, it last for a few seconds then stops.

Any help appreciated!

 

[Mikeyboy]

Suggest you also post this query on the screwfix site .You wil obtain a reply from :watersystems : , a big fan of thermal store type of system .Back to your thread .Wholesale gas prices , according to which newspaper you read , have risen by 60% in the U.K. , within the last year and accordingly all suppliers have increased the cost to domestic users .Other points to consider , is your new home larger with more domestic hot water outlets ?Are there more and larger radiators than in your previous house ? Are you using the same energy supplier ? Is your new home , a new or older property , as this has a bearing on how much energy is used to maintain a comfortable temperature , ie , older properties are not as efficient as new build in retaining heat . There is also a possibility that your gas meter is over-registering your gas usage .British Gas can test your meter , but , they charge you for this service . Also there may be a leakage of gas on your pipework , disappearing to atmosphere , and you are paying for this . There are other possibilities of course , but the previous suggestions are food for thought .Anyway , time for bed ,hope this is of some help to you . Other advice will no doubt follow tomorrow .

 

[Mikeyboy]

Re-read your post , as your house was built only 8 years ago , the insulation and thermal loss should be to current regulations .Did you record the gas meter index reading on the day that you moved in ? Ask your immediate neighbours ( if they have the same system installed) ,their normal costs for a gas bill covering the winter period . First port of call though , would be to your gas supplier .

 

[JohnD]

It has been an unusually cold winter, and fuel prices have rocketed, so that will explain some of the cost.

Odd that your hot water is excessively hot, isn't there a cylinder thermostat, or don't they work that way?

 

[Prabha]

I am aware that this original message was posted more than 2 years ago.
I will be grateful, if the original poster of the message let me know, if the problem has been sorted and if so how.

I have a similar problem, where the hot water boiler seems to run all the time, with a gledhill bolermate 2000 thermal store and even when no one is using the hot water and central heating is switched off completely.

Thanks.

Prabha

 

[scatmanjohn]

I will be grateful, if the original poster of the message let me know, if the problem has been sorted and if so how.

Hmmmm....the OP has only ever posted once...in 2006.

Now i aint a betting man, but if i was, i would bet my lives savings(which is not much) that you don't get a reply from him.

 

[ollski]

even when no one is using the hot water and central heating is switched off completely.

Thanks.

Prabha

The thermal store system maintains the temperature of the water in the cylinder constantly otherwise you would be unable to get hot water on demand.

 

[BigBurner]

Re-read your post , as your house was built only 8 years ago , the insulation and thermal loss should be to current regulations

8 to 10 years ago? far from current regulations.

He should compare house size and insulation levels to gas meter usage. Everyone has seen massive increases of fuel prices

 

[BigBurner]

I am aware that this original message was posted more than 2 years ago.
I will be grateful, if the original poster of the message let me know, if the problem has been sorted and if so how.

I have a similar problem, where the hot water boiler seems to run all the time, with a gledhill bolermate 2000 thermal store and even when no one is using the hot water and central heating is switched off completely.

Thanks.

Prabha

If the boiler is constantly on then there is something wrong with the control system. Have it seen too. What is the boiler set to? Put it on maximum and see if that stops the constant running.

Cranfield Uni in tests said that thermal storage can save 15% in fuel bills.

 

[BigBurner]

even when no one is using the hot water and central heating is switched off completely.

Thanks.

Prabha

The thermal store system maintains the temperature of the water in the cylinder constantly

Only when the time clock tells it to come on.

 

[Agile]

Oh dear! Water Systems is back.............

Thermal stores are a waste of time! Get yourself an unvented cylinder!

 

[ollski]

even when no one is using the hot water and central heating is switched off completely.

Thanks.

Prabha

The thermal store system maintains the temperature of the water in the cylinder constantly

Only when the time clock tells it to come on.

The timeclock only tells the heating to come on generally although there are many variations. However if you ran the store on a timer you could have a 20 - 30 minute wait for hot water.
I know there are timed versions but the basic principle of the thermal store is theat it constantly sits around 62 deg.

 

[Agile]

I know there are timed versions but the basic principle of the thermal store is theat it constantly sits around 62 deg.

The instructions for the Boilermate 2000 say that the boiler flow temp should be 82°C which makes it less ideal for condensing boilers!

Of course to get the economy it would be necessary to reduce that to about 70°C, I think that 62°C is probably a bit low though except in the height of summer.

Tony

 

[BigBurner]

even when no one is using the hot water and central heating is switched off completely.

Thanks.

Prabha

The thermal store system maintains the temperature of the water in the cylinder constantly

Only when the time clock tells it to come on.

The timeclock only tells the heating to come on generally although there are many variations.

Variations in time?

However if you ran the store on a timer you could have a 20 - 30 minute wait for hot water.

How do you figure this out?

I know there are timed versions but the basic principle of the thermal store is theat it constantly sits around 62 deg.

Yep, and it can be off during the night.

 

[BigBurner]

I know there are timed versions but the basic principle of the thermal store is theat it constantly sits around 62 deg.

The instructions for the Boilermate 2000 say that the boiler flow temp should be 82°C which makes it less ideal for condensing boilers!

Of course to get the economy it would be necessary to reduce that to about 70°C, I think that 62°C is probably a bit low though except in the height of summer.

Tony

Totally wrong.

The Gledhill manual says this:
Boilers should provide a flow temperature of 82 ± 3°C but temperatures as low as 76°C will allow the BoilerMate 2000 to provide a satisfactory performance.

76C. If a whole bath is run off and the store temperature is around 10C, the boiler will raise that water say 35 to 40C. 10C returning to the boiler will guarantee high condensing operation. Even if the condensing boiler is set to 80C, 80% of reheat time will be in condensing mode and even more if set to 76C.

At at return water temperature of 30C, 70 to 80% of latent heat is recovered. At 35C only 50% is recovered. A big difference in efficiency for only 5C return water difference. The thermal layering of a thermal store and the plate Heat X pumping water into the bottom of the cylinder less than 30C, ensures that when in operation the boiler is highly efficient recovering more latent heat than a condensing boiler directly coupled to a rad circuit and a coiled cylinder.

The modulating DHW pump ensures only very cold water returns to the cylinder. This gives a very cold spot at the bottom of the cylinder. This cold water then is pumped directly into the boilers return when the boiler is called.

The plates on the plate heat X flex and scale build up reduced. Scale is only a real big problem in excessive hard water areas like Reading.

Thermal store heat banks (with plates heat Xs) set to 70C give very acceptable DHW performance and condense very well. Thermal layering does it all for you. Get to understand thermal layering. The top of as cylinder can be 80C and the bottom 20C. The boiler on a Gledhill Boilermate 2000 should be set to maximum and the thermal store controls does the rest. The boiler is in the most ideal hydraulic environment enhancing efficiency and longevity.

The Gledhill is set to 55C at the taps by modulating the DHW pump. The CH will only operate when the store is over 60C. The pcb eliminates boiler cycling which can be very inefficient in thermal heat loss and burner start up. The vastly reduced stress on controls gives boilers a long life. Very neat indeed. If a preheated combustion air boiler is used, tertiary heat exchanger, cycling can reduce the high efficiency of these boilers. Continuous operation for as long as possible improves boiler efficiency and thermal stores do that.