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plumbers with G3.
my unvented cylinder install is effectively outside. (It’s a cupboard that’s part of the house but only accessible from a shed door outside. )There’s no Tundish as it discharges directly to the concrete floor and then the water flows under the door and down the path (which is when I notice there is a problem)
I’ve had someone service/safety check for the last few years and they’ve been ok with this set up but a chap before them seemed to think that the absence of a tundish was a show stopper for them.
who is right?
I don't know what purpose the tundish has other than to act as a funnel..... and you don't need that.
(I shall wait to be enlightened with regards to this as well as the uproar that will ensue when I say that I've had this megaflo in for 20 years and never had it serviced * 😱)
* I recharge the air gap myself as and when required
Ok, not qualified, but surely the discharge of potentially boiling water needs to be controlled? Ie thru tundish and waste pipe. ??
Yes, but his is simply discharging onto the ground outside - not in the house.
the hot water system has pipework that incorporates a provision for the discharge of hot water from safety devices to be visible at some point and safely conveys it to an appropriate place open to the atmosphere where it will cause no danger to persons in or about the building.
the hot water system has pipework that incorporates a provision for the discharge of hot water from safety devices to be visible at some point and safely conveys it to an appropriate place open to the atmosphere where it will cause no danger to persons in or about the building.
That’s correct, and the waste water must go to a nearby drain, or soakaway, as mentioned above, if it was 70 degrees water, you really dont want that spreading over the floor/ground.
No the water needs to discharge in a safe and ideally visible location. No need to be into a drain or soak away.
Thanks all. So @bear sounds as if plumber 2 was willing to be pragmatic but plumber 1 less so
Discharge is going to flow down the side of the house on a path, by the time it gets to the path I suspect it will have cooled down. The tank is tiny at 60L or so (although I realise that is still a lot of hot water!)
My problem is plumber 2 no longer seems to have a G3 cert on gas safe website whereas he did when I commissioned him a few years ago and so when looking for another it’s good to have a feel for what I have ‘might’ be ok as opposed to definitely isn’t ok
Would it not be a 5 minute job to cut the discharge pipework and fit a tundish?. Meet the letter of the regs, despite imho you meet the requirements as is? (I.e visible and safe discharge)
@steveb my concern is more if the discharge location is deemed to be unsafe as it is not nicely piped to a drain in line with the ‘norm’.
Meh..... mine goes through the exterior wall and then drips down from the first floor onto the ground outside.
Can't see the problem tbh... it's just a dribble when the air gap needs recharging and the tundish probably can't cope with a large flow.
Dig a small hole outside your cupboard/shed, chuck a bucket of gravel in and then set something like this on top.
If new plumber doesn't like the current set up he presumably can just fit a tundish and install a short waste pipe to the grid. (Maybe put an elbow below it so it's a bit more secure in the ground and not obviously full of gravel!)
Every cylinder I ever installed had a tundish included in the pack, and the fact that the regulations specify criteria for the tundish and the pipes leading to/from it suggests to me that it should be present:
3.50 Each of the temperature relief valves or combined temperature and pressure relief valves specified in 3.13 or 3.17 should discharge either directly or by way of a manifold via a short length of metal pipe (D1) to a tundish.
3.54 The tundish should be vertical, located in the same space as the unvented hot water storage system and be fitted as close as possible to, and lower than, the valve, with no more than 600mm of pipe between the valve outlet and the tundish (see Fig 04 page 9). Note: To comply with the Water Supply (Water Fittings) Regulations, the tundish should incorporate a suitable air gap.
3.55 Any discharge should be visible at the tundish.
3.61 The discharge pipe (D2) from the tundish should terminate in a safe place where there is no risk to persons in the vicinity of the discharge.
3.62 Examples of acceptable discharge arrangements are:
(a) to a trapped gully with the end of the pipe below a fixed grating and above the water seal;
(b) downward discharges at low level; i.e. up to 100mm above external surfaces such as car parks, hard standings, grassed areas etc. are acceptable providing that a wire cage or similar guard is positioned to prevent contact, whilst maintaining visibility; and
(c) discharges at high level: e.g. into a metal hopper and metal downpipe with the end of the discharge pipe clearly visible or onto a roof capable of withstanding high temperature discharges of water and 3m from any plastic guttering system that would collect such
Aside from everything else I don't think an open pipe located in an outside cupboard discharging water to a footpath in the depths of winter meets the "no risk to persons" criteria for 3.61, nor the discharge visibility in 3.55
My understanding of the need for the tundish is that if the overflow goes direct to outside and freezes and blocks then the cylinder could over-pressurise and may go 'pop'. With the tundish, if the outside pipe is frozen the water will flow over the edge of the tundish (not ideal) but at least the cylinder can still vent the excess pressure.
As your cylinder is outside anyway it presumably negates the need for a tundish as the whole pressure relief pipe could freeze anyway.