Frost protection thermostat settings ?

[dunkelly]

Hi all I'm off to NZ this winter and plan to leave my tube heaters on a frost stat for the winter . Can anyone suggest settings for an economical frost free boat whilst I'm away . Needless to say I'm charged an exorbitant rate for electricity so want to keep usage to the minimum . I was thinking switching on at 1 ' and off again around 5 . Does that seem sensible ?

 

[Boater Sam]

First job will be to establish the accuracy of the thermostats, many are grossly inaccurate. I would have them on at 3 degrees, electricity is cheaper than the alternative freeze up.

 

[Momac]

I set mine to cut in when the temperature falls to 5 degrees.
But with the boat in the water I don't expect many occasions when energy will be consumed.

 

[NormanS]

As Boater Sam says, check the accuracy of the thermostat. I have one which is set at 12°C, which probably cuts in at 6 or 7. That's for a tube heater down beside the engine.
Re extortionate rate: It's my understanding that it's illegal to charge more than the standard rate for electricity used. They can of course, demand a connection charge.

 

[geem]

First job will be to establish the accuracy of the thermostats, many are grossly inaccurate. I would have them on at 3 degrees, electricity is cheaper than the alternative freeze up.

Do you have plumbing below the floor or is it all fully drained? Have you drained the raw water side of the engine water circuit? Have you drained the calorifier? If you answer no to any of these, then you may want the heater set a little higher. The cost of repairs could be a whole lot more than your lecky bill

 

[wonkywinch]

Hi all I'm off to NZ this winter and plan to leave my tube heaters on a frost stat for the winter . Can anyone suggest settings for an economical frost free boat whilst I'm away . Needless to say I'm charged an exorbitant rate for electricity so want to keep usage to the minimum . I was thinking switching on at 1 ' and off again around 5 . Does that seem sensible ?

Do you mean 1 and 5 degrees or 1 and 5 am/pm?

Absolutely no point having time limited frost protection, a cold front can come through at any time.

 

[Boathook]

Do you mean 1 and 5 degrees or 1 and 5 am/pm?

Absolutely no point having time limited frost protection, a cold front can come through at any time.

I read it as temperature.

 

[wonkywinch]

I read it as temperature.

How can you switch on at 1 and off at 5? Stats don't work like that unless you had a special one where you can control the hysteresis.

 

[Boathook]

How can you switch on at 1 and off at 5? Stats don't work like that unless you had a special one where you can control the hysteresis.

Most stats when set at a temperature will turn on and of either side of the set temp. Possibly the cheap ones may well have a 5C range.

 

[wonkywinch]

Most stats when set at a temperature will turn on and of either side of the set temp. Possibly the cheap ones may well have a 5C range.

So how will the OP find one sufficiently slack that it will turn on at 1 and off at 5? And what will he set? 3 degrees? Is the hysteresis equal about the mid point?

 

[Boathook]

So how will the OP find one sufficiently slack that it will turn on at 1 and off at 5? And what will he set? 3 degrees? Is the hysteresis equal about the mid point?

I would think so.

I purchased some plug in stats (on line) to control some tubular heaters last winter. Worked well on the boat, but i noticed that the dial could be moved a lot between switching on and off. I never spent time working out the temp range but at around a set temp of 5C they kept the boat dryer.

Possibly, if I spent less time here, I could have done some form of experiment to find out the range

 

[Alex_Blackwood]

Most stats when set at a temperature will turn on and of either side of the set temp. Possibly the cheap ones may well have a 5C range.

Most stats I have come across have a differential of +/- 1 deg or 0.5 deg. e.g. a 1deg diff. set at 5 will work between 4 and 6deg.

 

[Stemar]

If you're in seawater, with a reasonable flow through, it's pretty unlikely that the boat will get below freezing point but, if you can't be around, it would be sensible to drain freshwater systems.

This, of course, assumes you're in the UK; even in Aberdeen, sea temperature rarely gets below about 6C. If you're in Svalbard, all bets are off!

 

[geem]

most stats I have come across have a differential of +/- 1 deg or 0.5 deg. e.g. a 1deg diff. set at 5 will work between 4 and 6deg.

I set my 1000w oil filled radiator to maximum on the stat. I installed a digital programmable thermostat switching the power to the oil filled rad. These are the type that you can set the on off temperature and the dead band. They have a separate sensor wire that you can install where you want. They are way more accurate than the inbuilt stat on my oil filled radiator.