Why is tech using “old” pipes?

[BachIsGod]

Hi everyone. I am getting a new oil fired boiler with a tankless coil. The boiler is a Williamson owt.

I noticed the piping this far has little copper and there are lots of old galvanized steel. I noticed on the parts list that some of the material should. It be used for potable water.

Should I be concerned?

 

[3fordasho]

Black pipe is what I see not galvanized. Black pipe is fine for closed pressurized systems but should not be used for domestic hot or cold water. I don't see any connections to the tankless coil which I assume is the connections just to the right of the pressure gauge. I bet the tech will use copper there. I don't see anything to be concerned about so far.

 

[peakbagger]

I see some shiny pipe that looks to be most likely nickel plated on the tankless coil. I do not see any galvanizing. It also could be stainless but far less likely. Boilers made for closed loop applications that are typical to a home are generally made out of carbon steel and cast iron. As long as its closed loop the oxygen in water quickly gets depleted and there is no more corrosion. As for the tankless coil, hopefully its made out of copper or stainless but sometimes to save money they put in carbon and figure the warranty will run out before it corrodes. on the potable side

A few notes, when Pex first came out and folks watching This Old House decided to put in radiant floors, PEX did not have oxygen barriers. The PEX would slowly allow oxygen in the systems and boilers were failing from corrosion. It took a few years of finger pointing between the boiler manufacturers and the PEX companies to agree to put in O2 barrier PEX which is now standard for heating. Some folks used to the prior issues still want to put in a heat exchanger to isolate the boiler and the PEX. This O2 barrier is not need for potable lines as they are made of corrosion resistant materials and costs less so the temptation was use the cheap stuff for heating as well as potable.

IMHO Any new fired oil boiler should be specified as a cold start capable type boiler that is capable of being left cold when its not needed with an external hot water maker. Many old boilers when they are allowed to cool between firings leak and thus are limited to continuously hot operation. Tankless coils have very low seasonal efficiency with an older style continuously hot boiler as the boiler stays hot 24/7 while the hot water demand is usually just one or two peak times a day. The far more efficient approach is a cold start boiler with a "hot water maker" insulated storage tank sitting next to the boiler. The boiler stays cold most of the day with the hot water being supplied from the hot water maker that is heated by a separate zone off the boiler. This reduces the boilers standby loss but when a lot of hot water is needed the boiler can fire as long as needed. Further efficiency can be obtained by putting a timer on the zone circuit that controls the heat in the hot water maker tank. That timer can be set to ignore the temperature switch in the tank at night and during unoccupied day time periods. The rule of thumb is a tankless coil on a hot boiler eats up 1 gallons of oil a day with no hot water demand. Far better to either do a hot water maker on a cold start boiler and blank off the tankless coil. Or go with a separate Heat Pump Hot Water heater (your local utility may give you partial rebate). HPHWH are typically 3 times more efficient than heating with oil somewhat offset by your cost for power versus oil. You also get free de-humification in your basement as side effect. Tankless coils are cheap to install and do not take up a lot of space and that's about their only pluses but the long term cost for a typical residence is high.

 

[Bad LP]

So far all looks fine but I do question using a tankless coil versus indirect or other water heating appliance.

 

[maple1]

So far all looks fine but I do question using a tankless coil versus indirect or other water heating appliance.

My thoughts as well.

If I was putting oil back in (yanked it all out 8 years ago), it would be a cold start boiler & indirect DHW tank.