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Post by AlexSquared on Jun 7, 2016 5:09:47 GMT -5
Hello all,
This might be a dumb question to all of you, but we just moved in to a new flat that has a Powermax 155x (never had this make of boiler in any of my flats before) and I wonder how can I have HW on demand? I tried the HOT WATER CONST switch and also the 24-hour HW programmer setting but they both seem to keep the boiler on all the time, even if no hot water is requested (so I expect costs would go up with this setting). In my previous flats, the boiler would automatically turn on to heat the water whenever the shower or a hot tap was switched on, can I have the same functionality with the Powermax?
Thanks,
Alex
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Post by northpole on Jun 10, 2016 6:58:32 GMT -5
The Powermax 155X is a thermal store boiler, and does not behave like the combi boiler you may be familar with. A large tank of water is maintained at a constant temperature of 80 degrees C; with hot water being heated by an externally-mounted heat exchanger, which transfers heat from inside the tank to cold mains water. Hence the boiler may not come on immediately when running hot water, but will eventually do so when the temperature inside the tank has fallen. Likewise, the boiler may come on even when no hot water is being run, if the contents of the tank have cooled significantly below 80 degrees. The boiler is not heating the tank's contents continuously, even when the timer indicates it is 'On'. Water from inside the tank itself circulates through the radiators when the central heating is operating. The Powermax design is in fact very efficient provided it is maintained correctly, and you should be no worse off in running costs than with a combi boiler. You might want to look at the User Manual here: www.powermax-repairs.co.uk/Powermax%20user%20instructions.pdfThe same website contains much useful information about the Powermax range. |
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Post by Richard King on Sept 12, 2016 10:01:38 GMT -5
We've noticed the boiler cycling on every couple of hours, to maintain the temperature of the store. So we tried turning the system off overnight and just switching it back on for hot water in the morning, so save a bit of gas.
What puzzles me though, is that if, when it is switched off, you draw hot water it goes cold after just a couple of seconds. Should it not still be heated by the water in the store - even if the system is not running???
Is this as it should be, or is this a sign that there might be a fault?
TIA (and many thanks for all the invaluable info you make available, Mike!)
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Post by Richard King on Sept 12, 2016 10:09:54 GMT -5
LATER:
Having done a bit more reading - I see that cold water has to go through the external heat-exchanger to be heated - so I guess a pump has to be running for this to happen... So my next question is, does the pump run hot water from the store through the heat-exchanger continuously, or is there a switch sensing a pressure drop when a tap is opened??
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Post by northpole on Sept 22, 2016 3:31:48 GMT -5
There is a 'flow switch', which senses when a hot tap is opened and mains (cold) water is being passed through the 'cold' side of the heat exchanger to be heated. This should switch on the lower pump, which passes hot water from the store through the 'hot' side of the heat exchanger. Even if the timer is off, this pump should still operate every time hot water is demanded; and, unless the store is very cold, this will provide adequately hot water from the tap for quite some time. If this is not happening, it is possible the heat exchanger pump has failed; if you remove the front cover of the boiler, you should be able to hear and feel the pump operating when a hot tap is opened.
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