Boiler help.

Cue

Well-Known Forumite
A lot of the time the issue is that the condensate pipe is just too narrow. If you can, swap the external pipe for a wider one.

Ours is 2 inches thick outside would you believe…

Is there a reason that the condensate can't be directed into a drain inside the house?

This would seem to be a less frost-susceptible situation.
If it’s not in the kitchen that can be a challenge. Ours is in the airing cupboard, only way that’s getting to an internal drain is by taking up the tiled bathroom floor… in hindsight we should have gotten it redirected when we had the bathroom done but we just didn’t think of it at the time.
 

The Hawk

Well-Known Forumite
My condensate pipe is also frozen, despite the installation paperwork confirming it is insulated to at least -10°c. I've been running all electric heating the last 3 days, with the air con / heat pump units (in 2 rooms) working overtime to heat the whole house.

My priority is now to get a length of trace heat cable fixed to the condensate pipe, so that this issue will not happen again.
 

Gramaisc

Forum O. G.
Over time, no amount of insulation will keep the temperature up, if there is no heat input.

Many years ago, I did get some 10 watts per meter, 240 volt, heater cable - I used it for the propagator in the greenhouse, but I may save a few meters from it, before I rebuild the propagator, although there's been no noticeable freezing problem here, even with ten days below freezing and a rather economical heating regime...

In Stafford, only the small heating header tank is in the roof, I did fit a thermostatic homebrew heater into that, that I can run via a timer, when necessary.
 

Cue

Well-Known Forumite
My condensate pipe is also frozen, despite the installation paperwork confirming it is insulated to at least -10°c. I've been running all electric heating the last 3 days, with the air con / heat pump units (in 2 rooms) working overtime to heat the whole house.

My priority is now to get a length of trace heat cable fixed to the condensate pipe, so that this issue will not happen again.
Ours is insulated but the last couple of inches go into a Y-shaped connector into the vertical drain for our gutter, can’t really insulate that bit…

I too am looking at trace heating to keep this at bay in the future, hell of a lot cheaper than getting the pipe rerouted. If you find any good ones do post them here
 

The Hawk

Well-Known Forumite
Ours is insulated but the last couple of inches go into a Y-shaped connector into the vertical drain for our gutter, can’t really insulate that bit…

I too am looking at trace heating to keep this at bay in the future, hell of a lot cheaper than getting the pipe rerouted. If you find any good ones do post them here
Will do.
 

gilesjuk

Well-Known Forumite
Seen many external condensate pipes even on recent installs using the 15mm plastic pipe. After a bad winter where many froze they recommended using a larger pipe on new installs but still seems like many don't.
 

Cue

Well-Known Forumite
Seen many external condensate pipes even on recent installs using the 15mm plastic pipe. After a bad winter where many froze they recommended using a larger pipe on new installs but still seems like many don't.
Yeah 2 inches is the recommended now, but even then in severe conditions it can still freeze up

Our plumber popped by on a very busy Monday to sort it, he was only able to fit us in because I knew exactly what the problem was already. Now I’m up one long bit of condensate pipe and know how to switch to it if it happens again, just needs a bucket really.
 

gilesjuk

Well-Known Forumite
I know someone who used to switch on an incandescent lightbulb near their water tank to stop that freezing up. Bulb supposedly had enough heat to help.

I guess some heating mechanism on the pipe could stop it happening. One that kicks in when it gets cold enough. Could be DC powered, a load of resistors would do it if you could get them warm enough.
 

Cue

Well-Known Forumite
I know someone who used to switch on an incandescent lightbulb near their water tank to stop that freezing up. Bulb supposedly had enough heat to help.

I guess some heating mechanism on the pipe could stop it happening. One that kicks in when it gets cold enough. Could be DC powered, a load of resistors would do it if you could get them warm enough.

You’re describing a trace heater, which you plug in and run along the underside of the pipe (externally), usually they have a thermostat to kick in near 0 degrees.

Not the cheapest things considering how simple they are electrically mind you, perhaps now that there will be higher demand for them someone will start mass producing them a bit more
 

Gramaisc

Forum O. G.
You’re describing a trace heater, which you plug in and run along the underside of the pipe (externally), usually they have a thermostat to kick in near 0 degrees.

Not the cheapest things considering how simple they are electrically mind you, perhaps now that there will be higher demand for them someone will start mass producing them a bit more
This is the stuff I used in the electric propagator - 10 watts per meter.

HTR-Heat-Trace-Tape-1.png

raychem_10btv1_ct_3.jpg

Live onto one wire, neutral on the other and the (slightly) conductive insulation provides a current path between the two, with consequent heating effect. You would need to terminate both ends of the cable, of course - I ran the 'far end' back into the terminal box, being careful to note which wire was which. There is no indication of 'sides' on the cover, but it's easy enough to check with a meter.

You would need a reliably accurate thermostat, to avoid freezing before it turns on, or wasting heat by turning on too early.
 

The Hawk

Well-Known Forumite
My condensate pipe is also frozen, despite the installation paperwork confirming it is insulated to at least -10°c. I've been running all electric heating the last 3 days, with the air con / heat pump units (in 2 rooms) working overtime to heat the whole house.

My priority is now to get a length of trace heat cable fixed to the condensate pipe, so that this issue will not happen again.
UPDATE: Most of what I need has now been purchased.

I've opted for commercial grade, constant wattage, 12W per metre heating cable from ESH Trace Heating of Telford. They do free delivery, but I opted to collect it from them. 7 metres of cable, plus a termination kit, came to £55.

To control the heating, I've purchased a 'Timeguard 4 hour electronic boost timer and fused spur' for £30. I've opted against a thermostatically controlled system, preferring to switch it on manually as required. Someone I know, who has already installed one, says that it only needs to be used very occasionally and a short 30 minute burst, in the coldest of temperatures, is all that's usually needed, whereas the thermostatically controlled ones tend to come on unnecessarily. The Timeguard timer allows you to choose from 5 countdown options, ranging from 15 minutes to 4 hours (see picture below).

In addition, to the above, I've purchased a cheap pack of external probe thermometers for £10, plus some additional pipe insulation to cover the cable and thermometer wire.

With a bit of mains cabling etc. the whole materials cost is around £100. Just need to get it fitted now.

3916.jpg
 

Cue

Well-Known Forumite
Hmm, at 10w a meter I might use a smart plug on it… I’ve got a temperature sensor out back so I’m halfway there already.
 

Gramaisc

Forum O. G.
A few points strike me.

I presume that the trace heating would only be necessary when the boiler is running - no burning, no condensate production, no problem?

It would only need to be heating when there is a real prospect of freezing conditions at the condensate pipe location.

Even with both of the above conditions existing, it wouldn't need to heat constantly, just enough to prevent a frozen plug being created.

A few minutes per hour might suffice, or one burst per day to clear the pipe?

It might take some experimentation to find the minimum satisfactory energy input...
 

The Hawk

Well-Known Forumite
A few points strike me.

I presume that the trace heating would only be necessary when the boiler is running - no burning, no condensate production, no problem?

It would only need to be heating when there is a real prospect of freezing conditions at the condensate pipe location.

Even with both of the above conditions existing, it wouldn't need to heat constantly, just enough to prevent a frozen plug being created.

A few minutes per hour might suffice, or one burst per day to clear the pipe?

It might take some experimentation to find the minimum satisfactory energy input...
The recommendation to me was two 30 minute bursts per day (first thing in the morning/last thing at night), only when there are significant sub zero temperatures.

A lot will depend on the level of insulation present, plus how long the cold temperatures persist. My pipe was rated to at least -10, but froze when the temperature never quite fell that low, but after a few cold nights (including a couple of -9s), followed by days where the temperature failed to get back above zero, so a cumulative effect.

Once my new system is in place, with the thermometers I've purchased I should be able to monitor the pipe temperature both before and after activating the trace heating cable, so I will be able to refine the conditions I need to respond to.
 

Cue

Well-Known Forumite
A few points strike me.

I presume that the trace heating would only be necessary when the boiler is running - no burning, no condensate production, no problem?

It would only need to be heating when there is a real prospect of freezing conditions at the condensate pipe location.

Even with both of the above conditions existing, it wouldn't need to heat constantly, just enough to prevent a frozen plug being created.

A few minutes per hour might suffice, or one burst per day to clear the pipe?

It might take some experimentation to find the minimum satisfactory energy input...
I can see a scenario where the boiler doesn’t flush its condensate reservoir for a while after it shuts off…

Either way it’s not a huge amount of power
 
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