My elderly mum's having her gas boiler replaced and says the installer says that according to current regs all the TRVs in the house must be replaced with a new type. Anyone know what this is about? (assuming I got the correct story).
Not so. If TRVs are already there then he is conning her. If none, then they are fitted in the sleeping areas to create a "temperature zone". There are other ways to create the temperature zone.
Utter bollocks.
The 'must be' is more like 'to meet lastest regs, must be' but there is no requirement to keep houses up to the latest regs.
Its a try on.
"bof" wrote
My understanding was that, if a heating system was being upgraded (I guess boiler replacement qualifies) then TRVs must be fitted to all barr one (the by-pass) radiator. If she already has TRVs of any type, then there is no obligation to replace these with a specific brand.
Phil
No. Read my post re: sleeping zones. There must be a boiler "control interlock" and the by-pass and wall stat provide this and this is not the only way to get an "interlock". This is clunky at best and best avoided on a condensing boiler as it lowers efficiency. Baxi make boilers that can have TRVs on all rads and no wall room stat. 133 HE plus combi and other Baxi system boilers too.
No.
The installer has either seen an opportunity to make more work (and profit) and is using the standard "it's the rules" line or simply doesn't understand the regs.
The building regs part L is the defining document (it's available online) but it refers to the "domestic heating compliance guide" (Google those exact words and you'll find it online). Table 2 on about page 16 gives the minimum control requirements for new and seperately for replacement systems. You'll see that there is absolutely no requirement (in your case) for TRVs of any sort let alone to rip out existing ones and fit new.
The "it's the regs" trick used to be very difficult to defend yourself against because you couldn't easily get the documents but with the new, more open style of government most such documents are readily available online. Whenever a tradesman tries that line on you try asking for a reference to the regulation - it soon shuts them up.
If you really want reassurance you could always call your local BCO and ask them. They are generally very approachable.
If you interpret that as "to meet current regulations (part Ln of the building regs), you need to install TRVs on each rad[1]" then that is about right assuming there are none currently fitted. There is no requirement however to replace existing TRVs with new ones - only ordinary manual rad valves.
[1] exclusions allowed for the interlock/bypass rad, and possibly small rads below a certain output IIRC.
Wrong.
I am not sure that is true.
Adding a new boiler is not a material alteration to radiators..where would it stop? anew boiler and by the way missus, we need to add cavity wall insulation to your home?
Indeed.
And that is new installations only. replacing a boiler could be classed as 'repair' in which case restoring to a state NO WORSE than prior to the repair is the norm.
Though that in itself would be a good idea if she hasn't already had it done. There are generally grants available via the local council to assist with the cost of this. We had it done last summer and even SWMBO agrees it's made this terraced, not particularly exposed, house feel much warmer.
Replacing a pump or a valve would be ok, but not the boiler itself.
Both the new and existing property versions of the regs documents refer out to the Domestic Heating Compliance Guide[1]
Table 2 specifies the "Minimum provisions for control of gas-fired central heating systems" (page 16)
For "Temperature control of space heating" it requires:
Separate temperature control of zones within the dwelling, should be provided, using: i. room thermostats or programmable room thermostats in all zones; or ii. a room thermostat or programmable room thermostat in the main zone and individual radiator controls such as Thermostatic Radiator Valves (TRVs) on all radiators in the other zones; or iii. a combination of (i) and (ii) above
The minimum requirements for a replacement are the same as above AFAICS.
You also need to meet the timed control requirements:
"Time control of space and water heating should be provided by: i. a full programmer with separate timing to each circuit; ii. two or more separate timers providing timing control to each circuit; or iii. programmable room thermostat(s) to the heating circuit(s), with separate timing of the hot water circuit. For dwellings with a total usable floor area greater than 150m2 timing of the separate space heating zones can be achieved by: i. multiple heating zone programmers; or ii. a single multi-channel programmer; or iii. programmable room thermostats; or iv. separate timers to each circuit; or v. a combination of (iii) and (iv) above Where the hot water is produced instantaneously, such as with a combination boiler, time control is only required for space heating zones"
[1]
Aren't you usually?
No, it's now controlled work like window replacement.
Similarly my Eco Hometec/Micromat comes in a version with a built in bypass valve and can therefore work OK with TRVs on all radiators. (It can also work without a room stat if required, or with one as in my setup, or with its dedicated room controller that has a temperature MEASUREMENT fed back to the boiler rather than just on/off so it can optimise the flow temperature according to indoor temperature - it has an outdoor sensor too).
It's still going strong several years after your initial recommendation (2 "identities" ago pre "IMM"). Recently it had an expensive repair - the diverter valve started leaking eventuallyl taking the actuator with it - but apart from that it has been very satisfactory.
Regards, Simon.
Sure, if replacing a RADIATOR? But a boiler? no.
AND you can still "repair" a single glazed window.
Yes, but these surely apply to new SYSTEMS.
Not to refurbing a system *part*..
Replacement of what? boiler? or radiator..
I cannot conceive that someone with a dead boiler but and otherwise functional system has to replace every valve on every radiator, add stats and timers where none existed, and bring the whole system 'up to spec'.
Your reading of the document and my reading are different. Maybe we are looking at different versions or something :-)
The version I have in front of me (freshly downloaded just minutes ago) says (in table 2) that *for replacement systems*:
"Space Heating Zones: As defined for new systems except where the boiler only is replaced, in which case reasonable provision for a space heating system would be to control as one zone."
then later the section you quote:
"Separate temperature control of zones within the dwelling, should be provided, using: i. room thermostats or programmable room thermostats in all zones; or ii. a room thermostat or programmable room thermostat in the main zone and individual radiator controls such as Thermostatic Radiator Valves (TRVs) on all radiators in the other zones; or iii. a combination of (i) and (ii) above
So, for a replacement boiler you only need to have one zone. Clearly that's been allowed so as to prevent the need for a major plumbing change which isn't in anyone's interest except the plumber. That one zone must have at least a room thermostat. It may also have TRVs but does not need to have them in order to comply.
The OP says that the installer claimed that the existing TRVs would need to be replaced with a new type in order to comply. To quote The Natural Philosopher, "Utter Bollocks".
See table 1 for minimum spec on replacement of a boiler, plus the end of the document for details of the hoops you can jump through to not follow them in some (rare) situations.
Also look at Ed's boiler replacement FAQ on the section about why you can't have "old faithful" back.
That would seem to be exactly the intention. Remember this is driven by politics and ideology.
It may soon be the case that if you build a new extension you will need to spend the equivalent of an additional 10% of the cost, "improving" other energy efficiency measures in the property.
You can't replace a boiler like for like either - it needs to be 86% efficient or better. Which de-facto means install a condenser.
Show me a condensing oil boiler ;-)
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