Professional Property Maintenance

My own tears scald me…

DANGER OF THE WEEK AWARD

Cowboy Gas Fitters

There is something wrong with this picture. Can you spot it? Well, if you can’t it’s the rubber hose connection that is hooking up the Pressure Relief Valve on the boiler to a bit of copper pipe which sticks out of the wall. Why is it unsafe?

The Pressure Relief Valve is meant to act as a safety in case the boiler builds up too much pressure and needs to vent. You’ll find this type of system in Combination Boilers. As your boiler heats hot water in the Central Heating Loop the water expands. As it expands the pressure increases. If you look at the gauge on most boilers you’ll see the pressure increase as the water heats up. That extra volume of water has to go somewhere or it will try to escape at the weakest point in the heating systems which could be a radiator valve, solder joint or the Pressure Relief Valve. if you’ve ever seen the Pressure Relief Valve pipe work leaking on the outside of the house it is most likely because the expansion vessel has failed.

As the water expands the extra volume is taken up in the expansion vessel which contains a rubber bladder which is negatively charged with nitrogen so that as the water pressure increases the rubber bladder fills with the extra water. So what happens when things go wrong?

If for example the pressure vessel fails and the pressure cannot escape as I mentioned earlier it will force it’s way out in the form of a leak. You’ll also notice that the pressure gauge will start displaying a lower and lower pressure when the heating is turned off . Over a period of time you will have to keep filling the system by way of the filling loop.

If however something else goes wrong such as some of the many safety devices fail it could be that the boiler pressure may increase to the point of failure. In other words it would want to blow up! Fortunately the Pressure Relief Valve is there to make sure that doesn’t happen. When the pressure increase to about double of what it should be (about 3 bar) the valve will POP open and scalding hot water will be vented to the outside of the property.

So back to the little bit of rubber hose. Do you suppose that that bit of hose, with no clips, will hold during the explosive opening of the valve and the subsequent flow of scalding hot water under high pressure? No. I don’t think so either. So to make matters worse, this room is a child’s play room with a little desk and toys sitting right underneath the boiler. A recipe for disaster and possible scalding of young children.

In this case I have seen the problem and the landlord of the property was informed as well as the tenant. The problem has been resolved with a few bits of copper tube and about five minutes worth of my time.

We see this type of issue all the time. There are lots of boilers which for some reason do not have the Pressure relief Valve hooked up at all. The valve is left pointing down under the boiler waiting to scald anyone who happens to be nearby if it pops. Take care and check your own boiler to see if it’s ever bee hooked up or is waiting to cause possible harm.