What the work is
If a tankless is already there, most of the expensive work was done once. The gas is sized, the vent is run, the condensate has somewhere to go. Swapping the unit is then a day's work.
The check that matters is whether the new unit is actually equivalent. Venting material and diameter, gas demand at full fire, and condensate requirements all change between models and between condensing and non-condensing units. We verify against the new unit's manual, not against the fact that something worked there before.
If the existing install was wrong, we will tell you. Replacing a unit onto an undersized gas line just moves the problem to a newer heater.
What is included
- Removing the old unit and setting the new one
- Reusing the existing gas, vent and condensate where they meet the new unit's specification
- Adding isolation valves if the old install lacked them
- Commissioning to the manufacturer's start-up procedure
- The permit where one is required
- Hauling the old unit away
What is not
- Upsizing gas or replacing venting, if the new unit needs more than the old one had. Quoted before we start
- Water treatment
- Correcting other people's work beyond what the swap requires, unless you ask us to
Why the old one failed matters
If the unit you are replacing failed early, find out why before you buy the same again. On this water the usual answer is scale in the heat exchanger from a unit that was never descaled, or was installed without the isolation valves that make descaling affordable.
A swap that does not address that buys you the same failure on a longer timescale.
What to ask anyone quoting this, us included
- Does the new unit need the same gas and vent as the old one?
- Why did the old one fail?
- Are isolation valves on it now?
