As mentioned earlier, my hot frog has failed. The fault was worn out bearings in the integral water pump which caused it to fail now and then. With no water flow, the heater shut itself off each time it tried to turn itself on
Bugone :-The hot frog is positioned in the pipework that goes to the cars internal heater matrix, so for any flow to happen when the hot frog is powered up, you have to have the heater matrix control tap in the open position which you do by setting the climate control temperature knob to hottest setting before turning the ignition off.
By comparison to the elements I am using in my brewery, the hot frog is a gentle warming device! I have always fancied fitting something with a bit more ooomph to the Insight.
The Brewery has various 4.5 kW elements that have fluid pumped through the element enclosures. They heat up to whatever the setting is on the digital thermostat in the circuit, so that is full power until such time as it is turned off.....(see bubbles Paragraph)
A recent brewery addition is £5 pulse width modulation circuits ( PWM ) switching 40 amp solid state relays, (SSR's) which then power up each element.
This new system is awesome, and the upshot of this is that with the mere twist of a knob I can have the 4.5 kW element running at any power I like...If I set it so it is turned on for half a second and then off for the next half a second then on then off etc...this gives an average power of 2.25 KW or 50% power, with the knob giving the ability to run anywhere between about 2% power to 98% power!!!
I think I will fit one of these elements into one of my stainless steel enclosures and back it up with a decent coolant pump, then fit the whole sheebang into the insight over the next few weeks, which will give me something akin to a "Kenlowe" system, but with a bigger element. I will then set the PWM circuit to some sort of smallish power setting in the region of 20 to 30%. I will then fit a "Bubble catcher" as described later and crank it up in small increments to see what happens.....
So, before anyone tries to fit a 4.5 kW element into their home made systems, I think that the massive power input would generate bubbles on the element rod, and they in turn would be able to eventually form an airlock and cause coolant system failure. This has always worried me, but the workaround would be to fit an opaque enclosed tank of coolant connected to the coolant system above where the engine bleed nipple is located, and with the bleed nipple permanently open. Bubbles would then enter the tank periodically and stay out of harms way and you could check the tank level as required and re fill it just before the air bubbles have displaced all the tanks coolant.