Drips from flow and return on rear of boiler

[bat400uk]

Hi there,

First time post, but I used to be a regular on uk.d-i-y in the olden days...

Anyway, I have two issues which I suspect are related. I have an unvented hot water system with a Megaflo tank and a Glow Worm Micron 40FF boiler. System is about 8 years old. Recently I have noticed a slow pressure drop on the gauge under the red vessel near the Megaflo in the airing cupboard. I have also noticed a very small amount of water pooling under the rear of the boiler in the kitchen. This mainly happens when the boiler first starts up.

I have spent a bit of time today working out where the drips are coming from behind the boiler and it turns out they are welling up in the tubing nuts where the flow and return tail pipes connect in to the back of the boiler. It seemed like the tubing nut on the return pipe was dripping more quickly than the one on the flow pipe, but they were definitely both dripping. The drip would form where the pipe goes into the tubing nut and then drop off the bottom of the nut.

Untitled

• bat400uk
• 7 Feb 2015
• 1

Anyway, I have a couple of questions:

• 
  Are the pressure drop on the red vessel and the leak related, as I suspect?
  How complicated is it going to be to tighten or replace the tubing nuts?

Thanks in advance for any advice you can offer,
Al

 

[Agile]

Most likely!

You can see if the nuts will turn.

However most likely the system will need draining, the sockets cleaned with wire wool, silicone grease added and then reassembled with new "O" rings.

Its the "O" rings which create the seal and not the tightness of the nuts!

If leaks like this are left for a while the metal becomes corroded and it can be almost impossible to repair.

Thats why regular servicing is so recommended to prevent problems.

Tony Glazier

 

[bat400uk]

Hi Tony,

Thanks for the reply. Ironically this problem started following an annual service back in November 2013. This was through a service contract with Scottish Power Home Comfort. Two of their engineers have since blamed the leaking on (a) the weather, and (b) a leak from the floor above, which is why I had to work out what it was myself!

I have now informed Scottish Power Home Comfort that the leak is coming from the tubing nuts and one of their engineers is coming out again tomorrow. I will be interested to see what they say this time...

If anyone's interested, here is the video I will be showing him if he says that it's not coming from the tubing nuts:
https://www.youtube.com/watch?v=TpZKsHuLBxM

Thanks for the advice - I'll follow up with what happens next!

Al

 

[Agile]

Have the system cold when he arrives.

The leak will evaporate when the pipes are up to temperature and he will think you are making it up!

Do tell us the outcome!

Tony

 

[bat400uk]

Good plan about having the system cold. I'll have to do without a shower in the morning!

Al

 

[Agile]

Heat the house and water at least an hour before he comes and that will give an hour to cool down.

Or use the immersion heater for hot water.

I dont want you to miss your shower!

Tony

 

[Plumbkinobi]

Should be picked up on a service but not a serviceable part, are they o rings or flat washers?

 

[bat400uk]

It says rubber washers in the manual.

Al

 

[Plumbkinobi]

Servicable part as in not replaced during a service

 

[bat400uk]

Servicable part as in not replaced during a service

But arguably it shouldn't have started failing within a month of the service if they had checked it properly?

Al

 

[Plumbkinobi]

Hmmm not so sure, if a boiler is water tight at inspection, I wouldn't expect an "engineer" to dismantle all the water holding parts to inspect the washers! Otherwise a service would take several hours and cost as much too

 

[Plumbkinobi]

Always though boiler "service" was a misleading term

 

[Agile]

Its not a problem with boiler normally and the "O" rings last the lifetime of the unit.

Its not possible to do anything apart from to just check that it is not leaking during the service!

Tony

 

[Plumbkinobi]

Think tony and I agree, are they o rings on that particular unit?

 

[bat400uk]

Fair enough, although you would hope that two other engineers from the same organisation would be able to work out where the drops were coming from once it was pointed out to them?