I hired Mark from House Depot to upgrade our old combi boiler to a modern tankless combi unit in our condo townhouse. We had originally agreed on a Navien unit, but on the last day before the install Mark determined that the Navien was too tall to fit in the space that we had, so we agreed to switch the unit to a Rinnai instead for a bit more money.
Mark went above and beyond as far as meeting my requests to have things plumbed so that no old plumbing lines were covered by new piping, and did a great job with the challenging, space-constrained installation. The resulting system layout was well done.
When a couple of issues did crop up after the install, he came by promptly, prioritising us whenever we have no working heat, especially in the middle of winter. The issue turned out to be a seized circulator in the tankless boiler which was replaced under warranty by the mfg.
One or two constructive criticism that I have is that the install did take longer than the original estimate we were given. I attribute this to two things: Mark's perfectionism and the space constrain of where the water heater must live and where the air intake/exhaust must go to in our condo townhouse. Still, getting an accurate estimate of project completion can be important when we as customer need to schedule other things around a project such as this.
