Last year, we sprung a big leak in the pipes between the pump and heater, and opted to bypass the heater. (It was around 90 every day.) The PB did the bypass, said we needed two new heat sinks at $95/each, recommended that we get a new heater instead of fixing the old one, and took all the connecting pipe. Honestly, I'm not sure what heat sinks are, but I know we can't afford a new heater. Since we opened early this year, I'd like to get the old heater fixed, but I'm reluctant to spend the money on it when I don't really understand it what's wrong. Can anyone educate me about heat sinks, old natural gas heaters, etc.? The heater is a Teledyne Laars XE, and we think it was original equipment -- maybe 10-15 years old. (We bought the house last year.)