We use a pump to pump water around the garden (Dabs Jet 102) We have lost two of these to frost over the last two years despite the last one being housed in a wood box with 50mm of insulation all round. This year I've decided to drain it down before the frosts start. My supplier tells me that draining it down will provide some protection but being of cast iron it will crack at anything below -8degrees even without water. Can this be right ?
Paul Mc Cann
can be if its got internal stresses, but most failures are from water in crack expansion or pure water expansion.
I depends on whether it suffers any knocks when cold. but it could.
No. There are hundreds of thousands of houses that have still got cast iron gutters, and there are lots of cast iron objects all over the UK which haven't cracked yet, despite being there for a very long time.
if there is water trapped inside it, that will quite probably crack it....the fact that you are going through them at such a rate is an indication that they aren't suitable for the job.
Why do they have to be cast iron?
Can't you fill it with some sort of antifreeze? (not car radiator stuff, which is poisonous)
The cast iron bridge at Ironbridge Gorge seems to have done all right.
Andy
That wrought iron surely?
No, it's cast iron, that's why it's so famous and historically important
- it was the worlds first cast iron bridge.
The whole area around there is interesting to visit - some good museums relating to industrial history of the area.
The first one lasted 17 years but the past two winters have been exceptionally severe around here. Last Jan we had -11 degrees of frost which is what took out the second pump.
Can't use anti-freeze as the water is often used for vegetables, green house etc.
I'm worried about being able to drain it down completely. We have a gas water on a boat and despite draining it down via its drain c*ck it still burst with the frost. Now I break the outlet connection to drain it down. That's an easy thing to do but doing that on this water pump would be a p.i.t.a. Might just insert some type of tee valve downstream of the pump and drain it from there. At close to =A3300 a pop I'm not eager to lose another one
Paul Mc Cann
No, it is brass monkey's appendages.
The pump and water will, eventually reach the outside air temperature, the insulation just slows down the rate at which it cools down/heats up. Outdoor pipes and plant should be insulated and trace heated, OR should have anti-freeze in. Both usually have frost protection strategies as well, e.g., in a heating/ chilled water system at air temperatures below 4 deg C, a circulation pump comes on and a boiler/ water heater maintains water temperature at 8 or 12 degrees.
If considering anti-freeze, propylene glycol is non-toxic, it is used as a sweetener in foods.Methanol could also be used; I don't know how either would affect plants, both are expensive. I'd be looking at a drain down.
+1 - I visited Ironbridge for the first time when back in the UK in June. What was really civilised was that you could buy a pay-and-display ticket in the first museum car park and use it in the others.
In article , fred writes
I think you'll need to look at the mechanics (fluid dynamics?) involved, if it is a horizontal installation with part of the water filled body below the drain point then it clearly will not drain completely. If however you re-mount it vertically then there may be more potential for complete draining.
I understand that car wash installations are supplied with a compressed air feed to blow water out of pumps and pipework when approaching freezing but even so they must be designed to blow out cleanly without leaving pockets of water.
As an alternative you may be able to add some electric heating to a well insulated pump body (with the pipework drained down) to stop it freezing but you'll need to monitor the temp during the winter to check that you've got the heat output right and of course it wont work if you have a power cut.
Is the pump submerged in water, like a pond or something. Pond pumps actually keep themselves warm when they are running. Could you find a way of keeping the pump running through the coldest spells / night time temperatures? The heat from the motor will keep it from freezing.
A submerged pump also has the water around it to keep it out of the most harsh part of the ground frost effects. Could you change the design of the pumping station to include a submergible pump?
--- Posted via news://freenews.netfront.net/ - Complaints to snipped-for-privacy@netfront.net
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.