I have just had a heat pump set up for a pool which runs off of a 20 amp circuit from the consumer box. To make it come on and off at the right time of day I would like to get a programmable timer added to control the operation of it. As it needs a 20 amp circuit I assume that the normal 16 amp timer switches that you get won't be big enough. Is it possible to get versions of these that are able to be included on a circuit this big?
Perhaps best to use a normal time clock (suggest a digital with battery backup) to control a contactor.
Sangamo make commercial timers (the big round ones) that have 20A rated contacts, eg http://www.tlc-direct.co.uk/Products/SGS254.html Not cheap though. If you want to use a contactor, they aren't cheap either. http://www.tlc-direct.co.uk/Products/MM22ALCFP.html
Thanks for that Owain, might just get up 5 minuites earlier till I can afford to get a sparky to put it in for me!
You really need to know the rating and inrush of the pump motor as 20A is a pure resistive load rating. I would go for a contactor and grasslin or grasslin based timer myself.
a note for Cronos Product recalls: detail Type: Water Heater Timer Manufacturer: GE Grasslin Model number: QE7 and Trac EQ7 automatic timing devices. Serial number(s): Not applicable. Manufactured dates: From 1999 to 2005 Recall date: 3-May-2005 Product Recall Notice. Faulty hot water timing devices recalled UP to 65,000 faulty hot water timing devices are being recalled over fears they could cause a fire, it was announced today. The Grasslin QE7 and Trac EQ7 automatic timing devices, used in homes to heat water, have a defect which can lead to the timer overheating, potentially causing a fire. About 35,000 Grasslin QE7 and Trac EQ7 timers have been sold in the United Kingdom since 1999, with a further 30,000 Grasslin QE7 timers sold in the Republic of Ireland. The products were made by German firm GE Grasslin, which is now contacting its distributors and electrical contractors to trace and recall each timer. Each will be replaced free of charge. Turn off The firm says householders with the timers should turn the main switch to "off" until the replacement is installed. When hot water is needed, turn the main switch on and push the boost button. After the water is heated, turn the switch to off. Do not operate the main switch or boost function while you are asleep or out of the house. A freephone helpline (0800 408 0048) has also been created for UK customers to contact the firm for advice and to arrange an appointment for the timer to be replaced. The helpline is open from 8am to 6pm daily until further notice. GE Grasslin has apologised to customers for any inconvenience. (Published in the Manchester Evening News newspaper on 5 May 2005) Freephone helpline (0800 408 0048) BB
Well bugger me I don't think I've ever fitted one of those, but shocking to say the least from a name I thought you could trust. I gather the problem lies in the ancillary controls not the timer mechanism itself.
Ho Cronos Just shows, you can't trust anyone nowadays. They've got 65,000 of these switches out there. Must be costing fortune to replace them all. BB