See full version: Is a combi boiler safe with NO mains cold water? (Urgent)
Basically this morning a hot tap would not turn off and was gushing hot water. I couldn't find an isolation valve for the tap so had to turn off all the water via the main stopcock. The only worry is a plumber I rung said that without the cold water going to our combi boiler, the heat exchange could melt itself and cause a lot of damage so we had to turn our heating off. more
Now correct me if i'm wrong but surely as long as the hot water setting is turned off on the boiler, the boiler should have two different heat exchangers so the hot water one would not melt due to not having any water to heat if it was off, and the heating exchanger works on a closed loop so should also be ok? [links]
Thanks again for any replies, the last thing I want is to destroy my boiler in such a cold winter. more
1. I live in your area. The 10 day forecast has no temps below freezing until NYE, when the low will be 27 overnight (inside your house will not get nearly so low). So in that sense it is safe to turn off the heat if you are leaving for Christmas/New Years. I would generally advise leaving the heat set to 50 since it is safer and you never know if you will be delayed returning home. more
Just throw the breaker on the hot water tank and you'll be fine.
posted by humboldt32 at 10:05 AM on December 23, 2015 [links]
I get the sense from the wording of your question that you are confused about how your home systems work so let's break this down step by step. more
Turning the breaker off only works with electric tanks, oddovid has a gas tank.
But as long as your boiler is in good working order, you shouldn’t even have to worry about this small risk. A combi boiler should shut down automatically if it detects a drop in mains pressure or if the temperature inside the system gets too high, as would happen without a supply of cold water. here
We sometimes hear of people turning off their water supply before leaving the home empty for a few weeks in winter. Their reason is that they wouldn’t want to come home to a burst water main caused by frozen pipes.
People often worry that turning off their water supply will adversely affect their boiler. The worry is usually caused by a fear of overheating, like boiling a kettle with no water in it, but in reality, it’s unlikely to cause any damage or risk. We’ll have a look at running your boiler without a water supply here, so if you’re worried, read on.
In all three systems, however, the water that comes out of your tap is not the same water as that which is passing through the heat exchangers. The water that is heated by the boiler is in a closed loop, and is heated, cooled and circulated continually. The water that comes from your hot taps will be either direct from your mains, from a cylinder or from a loft tank. Isolating your water supply will have no effect on the enclosed loop warming up radiators and exchanging heat to your tap water. You will only cut off the supply of water to the tanks, cylinders and taps. here
First up, if you have discovered a water leak anywhere in your home, whether that’s in your boiler, your storage tanks or anywhere else, then turning off your water at the stop cock should be your first priority.
There are three types of boiler, and they all provide hot water in different ways: here
System and heat only boilers will still heat up the radiators, and you may even get a bit of hot water from the cylinder which will dry up quickly when there’s no new water coming in.
People worry that turning off the water supply will affect their boiler, perhaps by overheating, like boiling an empty kettle. In reality, it’s not likely to cause any damage.
Turning off the water may not stop the leak immediately. If a tank is leaking, it may need to empty itself. A leaking tank will drain down to the level of the leak and then stop. here
First, if you have discovered a water leak, whether in your boiler, storage tanks or elsewhere, turning off the water at the stop cock should be the first priority.
It is common to wonder when we are supposed to turn off the water heater. Just like when we turn off all the things in the house when not in use. Different people have different views on the same things. This is why we asked some local plumbers on their point of view, because they let’s face it, they have more experience. The questions asked several plumbers was…should I leave my water heater on with the water off?
The water temperature will not drop that fast inside the tank, especially an insulated tank.here
If this happens to be the scenario for you, it is advised that you turn off the water through the valve on the heater to minimize leakage. But if the valve is broken, turn off the water supply. The reasons that may lead to this are: