Combi pressure drop & leak sealer

[Stenster]

Hi,

Was called to a property last week with a leak under a six grand oak floor.... somewhere?? The original company has been kicked off the site, by the looks of it they didn't pressure test it ( ???? ) floor went down on conc. block/batten, celotex & DPM/chipboard. We've had the LD guys in who pumped gas through it & went around with the sniffer. We took a section up under the stairs, that rubber floor glue is great stuff :32: , where the reading was high to find a lap in the DPM and a hole where the gas was tracking back, got to conc. nothing.

Went through all poss. boiler problems last week, checked EV pressure, nothing coming out of blow off on full whack anyway, heat exchanger fine, stripped it all out.... still dropping by about .75 to 1 litres a day. The pressure was fine until CH was switched on 10 days ago so the leak is tiny and only being pushed through when expansion is up.

WB told me in the end to dose with F4. It was fine for 3-4 days but now back to before.

Guy in charge of job wants me to dose again & I've told him about clogging up components & HE pathways.

What do you guys think about double dosing?

Dave

 

[oz-plumber]

What sort of system is it?

UFH or panels?

Either way, I would disconnect the boiler and put a pressure test on the pipework.

 

[Stenster]

Hi Oz,

Just standard 15mm copper runs sitting on the conc. block with DPC underneath to stnd. rads. PT already done at boiler with LT team & gas, dropping but could be anywhere. The 6k flooring is T & G 2.4m lengths, glued, no thresholds, one straight run and into 2 rooms so if it comes up the whole thing would cost the customer about 14k in total unless they can reclaim any ££ from the "Yeehargggh" builders.

 

[Centralheatking]

Hi Stenster - leaks in pressurised heating systems is my particular area of
expertise.

So this system is a pressurized, normal water underfloor system ? and has
an undectable leak which loses .75 ltr per day so it goes from operating
pressure to zero - how quickly 1x day 1x week

centralheatking

 

[solutions]

Hi Stenster - leaks in pressurised heating systems is my particular area of
expertise.

So this system is a pressurized, normal water underfloor system ? and has
an undectable leak which loses .75 ltr per day so it goes from operating
pressure to zero - how quickly 1x day 1x week

centralheatking

As I have read it based on Op's replies to other questions the system is not underfloor but leaks on pipe runs below floor to standard rads.
Op can the pipe runs be devide up in any way to pressure test sections. Testing at tge boiler is only going to confirm there is a leak not where on the system it is. Is there a second floor with rads on the same loop? How did you establish it was on the ground floor below the oak or us that what the LD guys and gas detection determined?

 

[Stenster]

Centralheatking,

Believe it or not it was about 1.5 litres a day when we first went there. Because it's block and beam floor with pipes on top of it then everything else on that it's obviously going down into the footings. Since the Fernox went in it's about .5l per CH run, that's twice a day. They found spots on the TI camera but we taped bolo roll onto electricians rods, got right down there and it's just dead tee by the looks.

Yeah, cold it just sits there forever at 1.2 bar, CH on...goes up .2 as you'd expect, soon as the CH goes off it slowly drops to nothing.

Stenster

 

[Stenster]

Just stnd. 15 copper, sweated joints. We went all around the property not a sign of any marks on the ceilings and it's just been skimmed and painted so we should see something with all that water going into the system.

One thing is the flooring we managed to get up in the cupboard was the haphazard pipe marking on the chipboard, very rough pencil squiggles. More worryingly is the screws though into the battens, all over the place. We were told it was a floating floor with no fixings.

The d/s is served with one long F & R that drops down behind a stud in the kitchen an loops in radial to all rooms.

I reckon it was pressure tested and it's been "nicked" with a screw.

Reluctant to put another dose of F4 in but.....?????

Stenster

 

[Centralheatking]

Ok turn off the valves to the boiler (WB by sounds of it) close all the rad valves
then pump the whole system on mains pressure as far as it will go up - go up to
3 - 4 bar if you can get it.

This is no problem the system may already be stuffed - just break it to find out -where .

Look for radical leaks and leave the test on for all day - see what happens
the leak might show its face - look, listen and observe.

BUT GET A DISCLAIMER SIGNED BY THE OWNER BEFORE YOU DO THIS CHK

I have more after you have done this bit

 

[Neil K]

Ok turn off the valves to the boiler (WB by sounds of it) close all the rad valves
then pump the whole system on mains pressure as far as it will go up - go up to
3 - 4 bar if you can get it.

This is no problem the system may already be stuffed - just break it to find out -where .

Look for radical leaks and leave the test on for all day - see what happens
the leak might show its face - look, listen and observe.

BUT GET A DISCLAIMER SIGNED BY THE OWNER BEFORE YOU DO THIS CHK

I have more after you have done this bit

Agreed. Thats all you can do at this stage of the game

 

[lame plumber]

daft question time, have you isolated the boiler and checked for pressure loss in rads and boiler seperately. Only asking as I had similar a few years back and eventually traced it to a pin holed heat ex draining into the condensate drain, seems older wb with the old rectangular hexs are are prone to leaks internally, took a while to prove that one and I had to strip down the hex to see the weeping in the end.

 

[Alpha man]

Heat ex isn't dripping through condense side?

 

[Stenster]

One of the late non condensing models

 

[Stenster]

The Heat exchanger was the first thing I went to, isolated the F&R at boiler, cranked pressure up and ran the hot. The 24i is late non condensing model.

 

[Stenster]

Cheers Centralheatking,

I'm not sure they would go for that as it's an old couple who have just had 7 months of having their house knocked about, all decorated, tiled, carpeted and looking the way they want it. Moved all the stuff back in ....now this.

I will put this to man in charge but flooring would need to come up anyway if we did this.