DANGER OF THE WEEK AWARD

Bad Heating Engineers (Lots of them!)

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This weeks cowboy award goes to the installers and service engineers of a heating system which has been plagued with problems since it was installed three years ago in a new build townhouse in Manchester City Centre. This one really highlights just how badly things can go wrong when a properly designed system is installed by inept engineers and then looked after by another team of inept engineers.  Our fist view of the building was when we were invited around to try and find a leak believed to be coming from an upstairs shower. The signs of leakage could be seen through the three floors directly beneath the en-suite that contained the shower.

When we arrived at this modern four leveled property we were shown the signs of leakage on the main, first and second floor. The owner thought that water might be leaking from a third floor en-suite bathroom so we started there. After a thorough look around it was not apparent where the water was coming from. We could feel wet pipe work on the lower floor via purpose built access panels but couldn’t see from whence it came. Most of the dry-lining was hung over steel stud-work  so we returned a few days later with the intention of using a bore scope to view the pipe work hidden in the walls and above the ceiling. I did however note that the pattern of stains was also leading to an upper floor boiler room containing a system boiler and unvented cylinder.  The tundish for the boiler was hidden in the back of the closet and I noted that was producing a steady flow of steaming hot water. The water was being ejected from the boiler via the pressure relief valve. Not good!

The water must have been running for a some time as the paint behind the tundish had blistered off to the dry lining. Crystals at the top of the tundish where  forming into stalagmites! The pressure on the boiler was also high registering just under three bar. Everything pointed to the internal expansion vessel being either damaged or just low on pressure. We returned with an external expansion vessel and pressure relief kit and while isolating the boiler to drain it we discovered that the filling loop had been left open just a crack.

The stupidity behind leaving the filling loop open just a crack is that if the pressure on the heating system is dropping too quickly (i.e. a few days) the ‘engineer’ will leave the valve open just a crack with the intention of allowing fresh water to keep topping up the heating circuit. IT DOESN’T WORK! In the end it just ends up overpressurising the system. Once the system is over pressurised; above three bar the pressure relief valve opens and lets excess pressure (and water) escape. The pressure relief valve then gets full of heating system nasties like grit, debris and sludge so that even if it were to close it would never seal properly thus allowing the pressure to escape continuously thus needing replacement. Also it should be noted that as the pressure grows to three bar with the pressure relief valve still closed some radiators, valves and pipe work joints might start leaking as a by product of too much pressure. So even after repairing or replacing the damaged expansion vessel and pressure relief valve there may be other areas where water is leaking out or air is leaking in. The latter is VERY hard to find.

So back to our story. While isolating the boiler we also noticed that the immersion heater was switched on. As there was no timer control on the immersion that means that it may have been on for some time. We switched it off and installed the new expansion vessel kit and then re-pressurized the system and fired up the boiler. We discovered two more small leaks from inside the boiler and with those sorted we left the property for a few days in hopes that the wet areas throughout the property would dry up. That would indicate that the water from the tundish may be leaking somewhere within the floors or ceiling but at least we would know what we were looking for and target the search instead of drilling holes all over the place for the borescope.

On our return visit yesterday we were happy to see areas where water was present now dry. We will follow up with one more visit next week just to make sure we have found everything. It was also apparent that once we switched off the  immersion heater that the hot water cylinder (unvented) was producing no hot water which implies a motorised valve or wiring fault which we will sort out on our next visit.

So to highlight all of the problems (in order of suspected breakdown) that nobody else seems to have found or repaired in three years:

1. falling pressure causing the boiler to shut down
2. filling loop left open just a crack to allow water from the mains to continually flow into the heating circuit
3. leaking water clearly seen at the tundish  (as in the pictures above) whether boiler was running or not as the water pressure was always too high
4. over pressurisation of entire heating system pointing to the possibility of further leaks once this issues has been sorted
5. several small leaks in the boiler all located nearby the pressure relief valve and pipe work leading to the internal pressure relief canister
6. unvented cylinder not being heated by the boiler but via the immersion heater which has been has been running 24/7 for who knows how long

So all this work from a boiler that installed in a new build project with all new materials and on a boiler which also has full breakdown cover. The lesson is simple. Find a qualified engineer who understands you heating system and is qualified (ask for qualifications!). Not ever heating system is the same and some engineers who are fully qualified to install may not have what it takes to diagnose and repair. Also, even engineers who have experience with for instance a combination boiler may not be licensed to work with unvented cylinders so may not know what to look f0r in any instance.

If you think that a yearly service contract or insurance scheme might have helped out here then think again! An engineer from a very well nationally known British gas company was on site the day after we viewed the initial problems and told the homeowner that he didn’t  see anything wrong. Everything was working as it should. Yipes!!

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