Maintain a rolling boil in cold conditions

[dougieorr]

To minimise mess through boil-overs, carelessness, clumsiness etc..., I tend to do my all-grain brew-days outdoors on my 3 level brew table (then chill, pitch & move my fermenter indoors).
My boiler / hlt is a 1500W electric 35L tea urn with thermostatic controls from 30C - 110C.
I have used this successfully for several years & it maintains a rolling boil for 90 mins - e.g. 33L start volume --> 28L end volume at end of boil at 110C - never had any issues.
Yesterday I noticed that the boiler was often cutting out when I wanted a full rolling boil, without me changing the timer or thermostat.
I restarted it a few times over several hours - as it still contains nearly 33L, I am presuming that it has never successfully boiled for any period of time.

Yesterday was fairly cold, approx 2C (I probably haven't brewed in such cold conditions).
Questions
- It is too cold to use the boiler in these conditions - the instructions do not mention operating conditions.
- Could it be that the thermostat works by comparing the ambient temperature of 2C with the required temperature of 110C & cutting out before boiling.
- Would it help if I put insulation around the boiler when it is in operation
- Anyone else had this issue
- Any other suggestions, other than brew indoors - although my garage won't be much warmer

 

[LeeH]

Link out the stat.

 

[Obadiah Boondoggle]

Is the element in direct contact with the water? - in my case I was having a similar problem. My heating element is not in direct contact with the water and heats the floor of the boiler. What I realised was the floor of the boiler was covered with a thin layer of hard "baked on material" that was "confusing" the thermostat. Cleaned it off and it's been fine since

 

[dougieorr]

That sounds like the cause & the temperature was just coincidence. I will empty this boiler into another to complete the brew, then check this boiler & remove any thin layer of hard "baked on material". Cheers Dougie

 

[Obadiah Boondoggle]

That sounds like the cause & the temperature was just coincidence. I will empty this boiler into another to complete the brew, then check this boiler & remove any thin layer of hard "baked on material". Cheers Dougie

Hope it works

 

[dougieorr]

Decanted brew into other boiler & checked original boiler
Very little scale - Edinburgh soft water
Filled with water only & it did rolling boil OK

Think I have identified the problem- didn’t use my hop spider for this brew & just added free flowing hops to boil
Based on scale likely to confuse thermostat, I suspect hops did likewise
May try another brew to try it out - you can’t beat working from home