Does this sound right or is it a contractor's shorcut?

[WorldPeace]

I recently had my 10 year old tankless water heater replaced with a similar model by a professional plumber.

The plumber didn’t replace every part though. Actually, he used many of the previoius parts and I was wondering if it was acceptable. They did replace the 2 new vent adapters at the top of the unit (that came with the unit) and added new stainless steel vents until it reached the nearby ceiling. However, that is all that was replaced.

They didn't replace any parts of the vent past initial ceiling wall. Parts of the vent that went through a small section of open space before going through the roof and the outside terminal were the original parts. I asked if this was ok and they said that since the original vents were made from stainless steel, the exhaust vents and terminal didn’t need to be replaced. I was also wondering if they should have checked the outside flashing and other possible problems but nothing was done.

They also ended up using the same old pressure relief valves, the same copper tubing and black pipe. And didn't test the incoming gas pressure, the exhuast CO2 content in order to adjust the internal fan. Etc.

I was wondering if this is normal or else I was scammed.

Thanks everyone for your help. I just pray i didn't get scammed. I don't want to go through another ordeal.

 

[Dana]

Stainless venting is very expensive, and isn't prone to failing under normal operation.

Pressure relief valves can go for decades, and unless it's seeping/dribbling an still works when you flip the lever so that you know it isn't seized shut, there's no real reason to replace it.

Not all plumbers are burner techs, with the equipment knowledge of to test & adjust combustion efficiency, but unless there's reason to suspect a gas pressure issue or the new burner's max BTU input is dramatically bigger than the one it replaced it's probably not a disaster. The manufacturer's installation and commissioning instructions should have been followed though.

Details such as the equipment model and make are usually relevant.

Does the thing fire up reliably, and control temperature well across a wide range of flow rates?

What was the other "ordeal"?

Why did you replace the old one? Most tankless units are good for ~20 years on the heat exchangers unless the heat exchanger was allowed to get too limed up.

 

[Sponsor]

 

[WorldPeace]

I had known that stainless steel was expensive with an elbow to be $40. But I would think that given the acidity of the condensate, that the entire stainless steel vent system as well as the terminal should have been replaced. But that's my uninformed opinion so that's why I'm asking the experts here. The inside of the old vent adapters looked pretty beat up on the inside so it worried me about the original parts above the ceiling - the vents and the terminal on the outside. I was wondering if this was permissible. I was hoping I could get a solid answer here.

I do know that the gas pressure and exhaust CO2 wasn't checked. The gas pressure was low because they never touched the regulator to turn it up. (There is a very long list of problems.)

At the end, when the heater is started and temp set at 130, the temp at the tap is about 120 after letting the water flow for a while. I don't know if that's normal drop in temperature when the tap is just 2 rooms away. Of course, I don't know if the domestic water lines are insulated in the ceiling but the weather was not cold.

Another thing is I don't necessarily think how the final product "looks" is an absolute indicator but it does kinda' show how much pride the plumber has in his work. I'll attach some pictures to show you what I mean. (He used the same old 10-year-old plastic tube for the new condensate trap.)

By the way, how do you tell the manufacturer and make of the vents? I want to see if the new and old vents are the same. Thanks.

And I'm know most people are honest but can someone tell me if it is a thing for a few untrustworthy employees to tell their boss that they bought all of the material necessary to replace the entire system but will actually only replace some of the old equipment and then, pocket the cash or the new materials?

Thanks for your help guys.

Stainless venting is very expensive, and isn't prone to failing under normal operation.

Pressure relief valves can go for decades, and unless it's seeping/dribbling an still works when you flip the lever so that you know it isn't seized shut, there's no real reason to replace it.

Not all plumbers are burner techs, with the equipment knowledge of to test & adjust combustion efficiency, but unless there's reason to suspect a gas pressure issue or the new burner's max BTU input is dramatically bigger than the one it replaced it's probably not a disaster. The manufacturer's installation and commissioning instructions should have been followed though.

Details such as the equipment model and make are usually relevant.

Does the thing fire up reliably, and control temperature well across a wide range of flow rates?

What was the other "ordeal"?

Why did you replace the old one? Most tankless units are good for ~20 years on the heat exchangers unless the heat exchanger was allowed to get too limed up.

 

[Dana]

The acidity of natural gas condensate isn't all that high, NOTHING like #2 oil exhaust condensate. Stainless can handle it, which is why the better condensing boilers use stainless steel on the heat exchangers (where the condensate is at it's hottest and most chemically active condition!) Unless the old vent was visibly pitted and corroded on the inside there would be no reason to incur the expense of swapping it all out.

Z-vent (stainless) is pretty generic and compatible between vendors except sometimes where it connects to the tankless. The near-tankless venting pieces for many tankless heaters are designed or specified by the manufacturer, and will often need to be swapped if they differ from the previous unit by very much. But the rest of it doesn't much matter if the new & old Z-vent were from the same manufacturer. At the price of stainless venting it's often cheaper to buy a condensing tankless to be able to use plastic venting instead, if the venting run is very long, and in general you'd only replace the necessary bits, not the whole thing unless it was obviously damaged (not likely, after only 10 years of residential service with a natural gas appliance.)

Is there some reason you're being coy about who manufactured the tankless, and it's model name/number?