Difference between revisions of "Central Heating Repair"
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== Fault-finding == | == Fault-finding == | ||
* No CH or DHW | * No CH or DHW | ||
+ | ** boiler working? - boiler fault-finding guide (Ed?) | ||
+ | |||
* No CH, DHW OK | * No CH, DHW OK | ||
** conventional | ** conventional | ||
+ | *** programmer, room stat or zone valve prob | ||
** combi | ** combi | ||
+ | *** programmer or room stat, (diverter stucK?) | ||
* CH OK, no DHW | * CH OK, no DHW | ||
** conventional | ** conventional | ||
+ | *** programmer, cylinder stat or zone valve prob | ||
** combi | ** combi | ||
+ | *** diverter valve if PHE design, flow switch or scaling if combined heat exchanger | ||
+ | |||
* DHW OK, some parts of CH not working | * DHW OK, some parts of CH not working | ||
** rad(s) compeletely cold | ** rad(s) compeletely cold | ||
− | *** balancing | + | *** balancing - try turning off other rads |
− | *** stuck TRV | + | *** stuck TRV - take head off pull up pin (carefully - can pull out and leak on some) |
− | *** completely full of air | + | *** completely full of air - bleed & find cause |
** rad(s) lukewarm | ** rad(s) lukewarm | ||
*** balancing | *** balancing | ||
Line 30: | Line 37: | ||
** rad(s) cold at bottom | ** rad(s) cold at bottom | ||
*** sludge | *** sludge | ||
+ | * CH on when should be off | ||
+ | ** All rads on | ||
+ | *** timer? room stat? zone valve? | ||
+ | ** Some rads on | ||
+ | *** reverse circulation | ||
+ | *** rad on DHW circuit - often in bathroom: may be design "feature" | ||
=== rads constantly need bleeding === | === rads constantly need bleeding === |
Revision as of 18:40, 15 February 2007
This article is about Central Heating systems using hot water as a heat-carrying medium. (Warm-air systems are sometimes found in the UK but their design and installation is not covered here. There is a discussion on updating existing warm-air systems here)
The article is about diagnosing and fixing a faulty central heating system.
There are separate articles about:
- Central Heating Design which will help you understand what sort of system you have
- Central Heating Operation for help operating a working CH system.
This article is a skeleton: the main points to be covered are listed but some or all still need to be expanded
Fault-finding
- No CH or DHW
- boiler working? - boiler fault-finding guide (Ed?)
- No CH, DHW OK
- conventional
- programmer, room stat or zone valve prob
- combi
- programmer or room stat, (diverter stucK?)
- conventional
- CH OK, no DHW
- conventional
- programmer, cylinder stat or zone valve prob
- combi
- diverter valve if PHE design, flow switch or scaling if combined heat exchanger
- conventional
- DHW OK, some parts of CH not working
- rad(s) compeletely cold
- balancing - try turning off other rads
- stuck TRV - take head off pull up pin (carefully - can pull out and leak on some)
- completely full of air - bleed & find cause
- rad(s) lukewarm
- balancing
- faulty TRV
- rad(s) cold at top
- bleeding
- rad(s) cold at bottom
- sludge
- rad(s) compeletely cold
- CH on when should be off
- All rads on
- timer? room stat? zone valve?
- Some rads on
- reverse circulation
- rad on DHW circuit - often in bathroom: may be design "feature"
- All rads on
rads constantly need bleeding
- air or hydrogen in system? (lighter test - with care!)
- corrosion:
- inhibitor?
- vented system? - pumping over?
- air
- pinhole leaks?
- vented system? - pumping over?
- corrosion: