We have a laars lite when we opened the pool for

turn gas valve to pilot hold down for 1 minute keep holdibg and light pilot hold for 2 minutes then turn to on

if pilot stays on check thermostat then control valve sounds like it's getting gas to it

You did turn gas Valve to On Position, Turned switch to On, Thermostat turned up, Have Sufficent water flow(Filter and Skimmer Cleaned and Checked). ? All these check out OK, Then you need a Qualifed Tech as it could be Several other things that require a Tech and Meter to test..

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It could be...does it open up at the point the heater shuts down? Check it with a DMM to see. It is more likely an issue with flame recognition off the pilot/ignitor. Check them for rust that would cause a faulty connection.

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John

Problem with the thermocoupler its not producing a minivolt of 250 plus that is needed to open the main gas valve

http://www.laarsman.co.uk

Miles

If this is a M/V heater you must have at least 400mv/dc to hold the pilot valve open. Check to make sure that the pilot is lighting, then hold the pilot valve down for about a minute. If the the pilot goes out you need to see what the m/v reading is. Chances are you have a bad pilot or gen. Replace.

is the tank a least 35 % full check for all the valves if not two solution replace ignition control or gas valve very hard to guess over this

The ignitor is probably bad. If you have an ohm tester you should have 50 to 70 ohms. It probably trys to fire 3 times and then stops.

If the pilot flame is not strong enough, it will not tell the gas valve to open, or if the gas valve is not getting the signal to open, it won't. Check all wire connections at the thermostat and gas valve. Check ground wires. Clean the pilot light and flame rod.