Low pressure in heating system, leaks appearing elsewhere!

rob w

Hi All,

Hoping someone here could shed some light on a plumbing problem I am having, so that I am armed with the proper information before dealing with my plumber on the issue!

House was re-plumbed about 8 years ago during renovations. Entirely new system put in incl. condensing boiler. After less than 5 years we started to get a leak on a pipe in the ceiling, resulted in the ceiling having to be cut out and leak 'fixed'. Shortly after that we started noticing issues with water pressure in the house - boiler cant heat enough water to fill a bath, water temp in shower much cooler in winter (think these are pressure related now?). We just thought the boiler needed servicing and got it looked at - plumber said it was in perfect condition and gave it a basic service.

A day after that, the boiler locked out due to low pressure, so we had no heating or hot water. Rang the plumber and he said that they must have 'accidentally left the filling loop valve closed', and told us it should be left open. So I opened it, pressure went up and boiler started working away as normal.

Since then the valve has been left open, or the boiler just locks out. Now I am pretty sure that shouldn't be left open, and could cause much bigger problems - if mains water is cut off, or the mains pressure goes up. Am I right in saying that? Does this mean we have a leak in the system somewhere if pressure cant be maintained?

Now the big problem, and I am wondering if it is a coincidence or if the above events have anything to do with it, is that a radiator valve has sprung a leak this week out of nowhere. I also noticed the wooden kitchen floor has started to warp in a small area too this week (Leaking rad is nowhere near the kitchen floor).

However I have just pulled out some kitchen cabinets today and found a leaking pipe (very slow leak, could be going years for all I know) which is dripping under wooden floor. Cant find the source of it on the pipe, but it seems to be coming out of a joint in the pipe insulation - I'm going to leave the plumber to find it! The pipe seems to be feeding the kitchen tap too and is possibly the same pipe that leaked in the ceiling a few years back, so I don't think it part of the heating system.

Sorry for the long post, but is it possible that the leaks now are somehow connected to the filling loop being left open on the heating system or is it just coincidental?

I'd appreciate any advice from the helpful people of this forum!

whizbang

Yes is the short answer.

After initial filling, the water in the heating system looses its corrosive properties fairly quickly, and ceases to cause damage.
If fresh water is continually refilling the system, the corrosive elements are being refilled also, and will eat any susceptible parts in the system.

One: get a new plumber.
Two: plan for a new boiler soon.

rob w

whizbang wrote: »

Yes is the short answer.

After initial filling, the water in the heating system looses its corrosive properties fairly quickly, and ceases to cause damage.
If fresh water is continually refilling the system, the corrosive elements are being refilled also, and will eat any susceptible parts in the system.

One: get a new plumber.
Two: plan for a new boiler soon.

Thanks for the reply!

Not good news, really annoyed at the incompetence of the plumber over this!! Now to find a new one, not an easy task when I have no recommendations!

How quickly can corrosion cause serious damage?

Also, ive noticed that there is often water dripping out of the boiler overflow pipe outside the house. Would you know if this is a problem with PRV or expansion vessel.....ive read a bit about it this morning....could this maybe be causing the low pressure as opposed to leaks?

Thanks!

cubix

Sounds like you may just be unlucky and have leaks in various spots unrelated. Started with the obvious ones you can see (under the kitchen & rad valve) and go from there. When you say there is water coming out the boiler overflow this may be the condense line and is normal if you have a condensing boiler. As you already suggested if your boiler needs constant topping up it would indicate its going somewhere.

agusta

rob w wrote: »

Thanks for the reply!

Not good news, really annoyed at the incompetence of the plumber over this!! Now to find a new one, not an easy task when I have no recommendations!

How quickly can corrosion cause serious damage?

Also, ive noticed that there is often water dripping out of the boiler overflow pipe outside the house. Would you know if this is a problem with PRV or expansion vessel.....ive read a bit about it this morning....could this maybe be causing the low pressure as opposed to leaks?

Thanks!

If water leaks out the overflow it does cause a pressure drop in a sealed system.But your running the system with the fill valve open so you dont know what pressure your running the system.
For starters,
1/Set the pressure in the system to 1 bar,CLOSE the fill valve.If the pressure is reading higher,bleed a rad to get it back to 1 bar
2/Then check the pressure on the gauge when the system if up to full heat
3/Check the pressure drop in the system over 24 hrs/48 hrs etc
4/ monitor the pressure relief valve for leaks
This information will be very helpful for the plumber to diagnose the system faults