How to find leak-moved from gravity to pressurised system?

[fluff29]

hi guys

Does anyone have any suggestion for our plumber to find a leak in our pipe work?

Background:
New Worcester 30CDI system boiler fitted in September with new rads but using existing 15mm pipes to rads and fitting stat to existing insulated water tank. Move from gravity fed to pressurised system. Tube of fernox sealer fitted after testing of system just incase of any small leaks. Any small bits of new pipe work at rads/running to new boiler location plus all valves are leak free. The Worcester accredited installer has offered to put another tube of sealer in. We are losing 0.5 bar over a 2 week period (or a bit less).

Issue 1:
The engineers at my work (don't work daily on domestic boilers) woukd be reluctant to put in more sealer as they think it would gunk up the TRV's etc. They have suggested getting the plumber back to pressure test the system, taking up to 3 bar slowly and listening for the leak.

Is this the only/best way to find the leak?

We know we will need to pay for the plumber to do this as all his joints are clean and it's possible we have a joint that has been leaking for years.

Issue 2:
We are using between 12-14 units per day on these cold days. Heating on to 20degrees on programmable stat for 6.5 hrs per day. Water timed for 4 hrs a day with stat on HW tank. We have 11 rads and 2 towel rails 180 sq meter house and it is not mega warm. Never even reached 20 degrees in the hall tonight (where stat is) and rest of house not even cosy. Although, we need to top up the pressure again. It's costing about £5 a day on this usage which coukd be £100 a month in the winter, which seems excessIve. I thought we woukd save money with a new boiler. Unfortunately I only moved in June so I can't compare bills fir last winter. Does this seem reasonable usage or could it indicate another issue?

Any suggestions we could get the plumber to look at?

Many thanks for any suggestions
Fluff

 

[fluff29]

Hi guys

Does anyone have any suggestions on how we can find such a small leak or do we just continue to top up every few weeks until it eventually gives fully?

TIA

 

[dilalio]

Could be anywhere!

First check all the pipework and fittings you can access... include rad valves. Use blue paper and try and keep heating off as small leaks can flash evaporate before being spotted.
Expose what you can and you haven’t said what floor structure you have... if suspended then you’ll need floors up to start tracing the source... you could try listening around doorways as this is a common place for nails/screws to pierce pipes.
There are leak detection firms you can call in who have all sorts of equipement - but cheaper if you can find it yourself by methodical investigation.

 

[ianmcd]

dont put more leak sealer in

 

[GoodDIYjob]

hi guys



Issue 2:
We are using between 12-14 units per day on these cold days. Heating on to 20degrees on programmable stat for 6.5 hrs per day. Water timed for 4 hrs a day with stat on HW tank. We have 11 rads and 2 towel rails 180 sq meter house and it is not mega warm. Never even reached 20 degrees in the hall tonight (where stat is) and rest of house not even cosy. Although, we need to top up the pressure again. It's costing about £5 a day on this usage which coukd be £100 a month in the winter, which seems excessIve. I thought we woukd save money with a new boiler. Unfortunately I only moved in June so I can't compare bills fir last winter. Does this seem reasonable usage or could it indicate another issue?

Any suggestions we could get the plumber to look at?

Many thanks for any suggestions
Fluff

Mains gas boiler?

Usage is mostly related to the size of the property, whether it is terrace, semi or detatched, the amount of rooms you are heating and the quality of insulation (in loft, cavity walls, floor slab etc. etc.)

For comparisons, ours is a small 1930s 3 bed semi, about 100m2, we have 6 rads and one towel rails. We have the heating on most days 5.30am - 10pm (16.5 hours). Stat on 18C-19C at different times. We use between 8 and 11 units a day in winter. That is about 90-120kWh per day. House is warm except kitchen which does not have any rads but eventually heat moves in there a bit.

Edit: Given the size discrepancy alone, in absence of further info it doesn't seem that far out of expectations.

If you do a heat loss calc or have an EPC with annual heat load it will give you a basis for estimating annual consumption using a degree day calc. But it will only be an estimate, and academic, you are using the gas you are using and the heat is going somewhere and your house is still not that warm...Meaning you need to turn up the thermostat or up the boiler temp a bit or fit some bigger rads (or combination).

The location of the stat may not be perfect if it is never satisified but if the rooms are not overly warm, fixing that won't lower consumption...

You can ask for a gas meter accuracy test but if it is within tolerance you will end up paying.


Your best comparison, if you don't want to go to the trouble of building calcs yourself is to ask neighbours in similar properties what their usage is. Taking into account times heating is used, hot water demand will be a smaller component.

 

[gasbanni]

.5 of a bar over two weeks seems like a weep or two not a big leak. Small weeps can evaporate and you won't find them.

You could try putting the pressure up to 3 bar and it's a case of looking everywhere you can to see if you can see anything.

Something sounds wrong as the house isn't getting warm ....do the rads get hot ? What's the thermostat setting on the boiler?

The setting on the room stat ......turn it up full for an hour and see if all the rads get hot. This will at least check if all the heating circuits are working.
Post the results to enlighten us.