I've just replaced the hot water cylinder because the old one was leaking. It's a vented indirect cylinder, heated by solid fuel in winter and immersion heater in summer.
I think there is something wrong with the new thermostat, as even on the hottest setting it cuts off at 40 degrees. Unfortunately I can't just pull it out and send it back because of the angle of the sloping roof - I would need to remove the tank again - a struggle getting all the pipe connections to line up.
So what I am trying is using an external thermostat, clamped to the tank about 1/3 to 1/2 way up. Initially I am using a spare probe type from a short immersion heater, pushed in through the foam insulation tangentially so that the tip lies alongside the copper cylinder.
This works with partial success, but the range of operation is so wide that it is wildly erratic in controlling the temperature. The point at which it clicks on/off is over 20 degrees, so I can have 40 degrees or 80 degrees actual temperature, but it's very hit or miss getting 60.
What I am now thinking of is fitting a proper sensitive tank thermostat, of the kind that clamps flat against the tank after cutting out a rectangle of foam. Will such a thermostat operate the immersion heater directly, or does it need a relay? I can find ones rated at 10 amps, but that doesn't really seem enough to switch a 3Kw heater.
Has anyone any thoughts or advice to offer?
I think there is something wrong with the new thermostat, as even on the hottest setting it cuts off at 40 degrees. Unfortunately I can't just pull it out and send it back because of the angle of the sloping roof - I would need to remove the tank again - a struggle getting all the pipe connections to line up.
So what I am trying is using an external thermostat, clamped to the tank about 1/3 to 1/2 way up. Initially I am using a spare probe type from a short immersion heater, pushed in through the foam insulation tangentially so that the tip lies alongside the copper cylinder.
This works with partial success, but the range of operation is so wide that it is wildly erratic in controlling the temperature. The point at which it clicks on/off is over 20 degrees, so I can have 40 degrees or 80 degrees actual temperature, but it's very hit or miss getting 60.
What I am now thinking of is fitting a proper sensitive tank thermostat, of the kind that clamps flat against the tank after cutting out a rectangle of foam. Will such a thermostat operate the immersion heater directly, or does it need a relay? I can find ones rated at 10 amps, but that doesn't really seem enough to switch a 3Kw heater.
Has anyone any thoughts or advice to offer?