My home had a tankless hot water heater that had developed a nasty habit of not turning on for small water demand like washing your hands in the bathroom sink. When it did turn on it would occasionally run wild temperature-wise and scald you in the shower if you were not careful. The Sun plumber showed up right on time. He took a look at my water heater and then after a quick phone call to the home office he announced the repair would cost me $255+. In the interest of getting our unit going again I said sure. There was never a mention that the repair procedure he was planning might not do anything to repair the situation. The Sun Plumber hooked up a small submersible sump pump which he had in a five gallon pail. Using a couple of hoses he connected his pump to special fittings my hot water heater had at the input and output for “descaling”. He then cycled vinegar through my heater for an hour. At the end of the hour he removed the bucket and we examined the liquid. Nothing. It was still basically clear. Apparently “scale build up” was not what was wrong with my water heater. Further analysis pointed towards a part that “might” be the problem. “Might” be the problem was not what I wanted to hear after paying out over $255 so far. This guy was not really knowledgable in my opinion, he was experimenting on me. He said that was all he could do, he would call me with a price for the replacement part. I paid him the $255+ and he left. Two days later he called me with the price of the replacement part he was recommending, it was another $250 plus $140 installation labor. I asked if he could quote us on a new replacement hot water heater and he said sure. My wife and I had already agreed if the total price was over $100 we were going to replace the heater rather than spend any more on this one. Two more days passed then the Sun plumber called with the price for a replacement heater it was over $2500 for a premium Rinnai model. I asked about the model number and gallons-per-minute and he had no idea. He said he picked this model because it had a very simple exhaust pipe that he could install. He also said he put himself in for six hours of labor installing the unit. I asked if he could recommend a less expensive model since we did not need anything near the capacity of the top of the line Rinnai. He told me he would call me back but after a week and a half I had heard nothing. Instead of calling Sun Plumbing again I called the Rinnai USA corporate office and started asking questions. They told me Sun Plumbing was not an authorized dealer and if I bought an installed unit from them I would have no factory warranty. They further told me that Rinnai dealers must go through factory training to install their products, high efficiency tankless hot water heaters are nothing to take chances with since you can burn your house down or blow it up with gas leaks. They recommended two local dealers, I called them both, got estimates and hired the lower priced estimate (who was the actual installer for the other company I called which was our propane supplier). The dealer stocks Rinnai hot water heaters and put me on their calendar for 3-days later. It took the two factory trained installers 1-hour and 45-minutes to install my new Rinnai tankless 6.5 gallon per minute hot water heater. They installed a new chimney through the roof and brand new valves and fittings for “descaling” the new heater (which is recommended every 3-6 months of use). I’m giving Sun Plumbing an F for several reasons. !. Upfront, they did not tell me the descaling might do anything, it was posed as a solution to my problem. It changed nothing, it was a total waste of money $255+ while Suns Plumber experimented on my hot water heater. 2. Sun plumbing was very slow to respond to inquires about fixing my problem. They were on time for the first appointment but after that it was confusion and a waiting game. At one point when I was texting with the plumber about my job he said he was too busy, call the office. I did, they made another appointment with the same plumber again and answered no questions. Nobody knew nothing. 3. Sun plumbing did not tell me they are not a Rinnai dealer (they buy Rinnai hardware through some distributor). The plumber made it sound like it was no big deal for him to install the new unit. He said he had installed them before but could not remember when the last one like this was. Overall it sounded like this plumber has plenty of work and did not want to mess with me unless it was at the ludicrous rate. 4. Sun was very slow to respond and in the end just completely dropped the ball and said nothing when I asked about a model that cost less than $2500+. When I did ask about the high price I was told “we do things quality, when it calls for 1-inch we put in 1.25-inch”. Was that supposed to make me feel better? They install bigger stuff than the job calls for so that means quality? 5. Rinnai told me that condensing type water heaters like Sun's plumber was recommending are not really recommended for use in this part of Florida because our ground water is too warm. What? The representative from our propane company said the same thing, condensing type units are for areas of the country that have much colder water coming out of the ground. We’re on a well, our source water temperature is 68-degrees year around. It would be a waste to install the condensing unit here. Obviously I won’t be calling Sun Plumbing back for anything ever again.