How can plumbing problems be mitigated? We find that on most emergency calls, the boiler pump is at fault. Are there any downfalls to combi boilers? Roy was awesome! installed my water heater in no time down to earth type of guy with great plumber background glad to have him as my plumber. It goes without saying that if you try all of this and nothing works, you may need to call a plumber but why not try it yourself first? We.