Dumb question about hot water heat temps

Johnny12

I know this may sound dumb, but on a hot water baseboard system, would the temperature of the outside of the copper pipe be the same as the temperature of the water inside the pipe?



The reason I ask is because the last service person I had out turned down the maximum water temperature of the boiler when he replaced a thermocouple. He did this because I had mentioned that I thought the water in the boiler was actually boiling when it fired, possibly due to sediment buildup in the heat exchanger. The problem is that this year, the system is having a lot of trouble heating the house. The boiler is not running constantly at all. Far from it, in fact. I measured the temperature on the supply side of the loop near the boiler with a fluke contact thermometer and it was around 135 degrees. This seems way too low to me. The radiators used to throw off the heat like mad, but now they don't feel very hot at all.



Thanks in advance for any input or assistance!

--John

Alan (California Radiant) Forbes

Temperature

The copper should be as hot as the water.  It sounds like your heat exchanger needs to be cleaned and the operating limit turned back up.  I'd be running that BB at 150-180 degrees.



What kind of boiler do you have?  I'd guess it's a Laars or another one with a copper heat exchanger.

Johnny12

It's a Weil McClain

It's a Weil McClain from circa 1985. It's blue on the outside housing if that means anything. Aside from just flushing the system out, is there anything else I can do to get the buildup out of the exchanger?

Ironman

Scale build up

The boiler will have to be isolated and de-scaling solution pumped through it.

rick in Alaska

infrared thermometers

If you are checking the temperature on your boiler output with an infrared thermometer and it is copper tubing, you need to paint the piping with some flat black paint in order to get a true reading . Has to do with the infrared of the thermometer and how it works. Sorry, it is late and I am getting brain tired and can't give you a better description  of the workings of the thermometer.

 Paint the pipe and you will be more accurate.

 Rick in Alaska

rick in Alaska

infrared thermometers

If you are checking the temperature on your boiler output with an infrared thermometer and it is copper tubing, you need to paint the piping with some flat black paint in order to get a true reading . Has to do with the infrared of the thermometer and how it works. Sorry, it is late and I am getting brain tired and can't give you a better description  of the workings of the thermometer.

 Paint the pipe and you will be more accurate.

 Rick in Alaska

rick in Alaska

infrared thermometers

If you are checking the temperature on your boiler output with an infrared thermometer and it is copper tubing, you need to paint the piping with some flat black paint in order to get a true reading . Has to do with the infrared of the thermometer and how it works. Sorry, it is late and I am getting brain tired and can't give you a better description  of the workings of the thermometer.

 Paint the pipe and you will be more accurate.

 Rick in Alaska

Johnny12

Boiler temp increase has helped

I bumped up the max heat on the control on the boiler, and that has helped a lot. I am about at the threshold now of where I start to get some boiling/air noise in the system, but it's not at the point it was before the service guy turned it down.



I am using a contact thermometer that I wrap around the copper, not an infrared, so I think it's pretty accurate. With the last temp increase, I saw about 167 degrees on the supply side.



The pressure in the system is around 12 psi. If I were to increase this a bit, to say, 20 psi, would that let me increase the water temperature a little more but suppress the tendency of the water in the heat exchanger to boil?

croydoncorgi

It's the Crud!

Can't handle all this discussion of boiling boilers!  On this side of the pond, the trend is to reduce boiler supply temperatures to maximise efficiency.  On a high efficiency boiler, 80C (175F) would be regarded as 'hot' these days but from other threads here and elsewhere, US practice tends to run hotter than that.



Anyway, at only 167F on the Supply close to the boiler, if the flow-rate is good, there should be no chance of boiling.  What's happening (probably) is that the boiler is full of crud and 'kettling' is occurring.  The crud sits on the bottom of the heat exchanger and insulates the hot metal from the water.  Then there IS local boiling, and a small bubble of steam forms, disturbing the layer of crud, then colder water contacts the steam bubble which cools rapidly and condenses, creating a mini implosion.  This process repeats thousands or millions of times per minute and creates the boiler noises.  Larger bubbles make a definite bumping sound as they collapse.  Smaller ones hissing or 'singing keetle' noises.



As has been suggested, the beast needs a clean!

Oak Park Electric

Pressurize this

Yes, an increase in the system pressure will help somewhat to stop the boiling, but you have to be  careful.  The more you raise the base pressure, the "smaller" your expansion tank becomes, and it will not be able to absorb as much extra volume of water.  Going up to 20 MAY be ok, but if not, you could end up with a relief valve pop or drip.  Really, though, I think croydon has the right long term solution.  Take the pipes off and flush that thing out.  That way, you can turn the temp up enough to get sufficient heat out of the baseboard.

Johnny12

Pressure increase helped

Thanks for all the help, guys! I bumped up the pressure a little bit, to around 15-16 psi, and that has helped. It is running pretty well now, all things considered.



I have no doubt there is crud in the heat exchanger, but I'm not sure if cleaning it out is worth it. The system is going on 26 years old, and the energy-efficiency tax credit that expires at the end of the year is a big incentive to replace the boiler. The other strike against the current system is that it is set up with a pre-packaged circulator pump that is pumping toward the boiler and expansion tank. I'm sure this is not helping the boiling and air noise situation.



The current system is 100k BTU input / 82k BTU output. What are some reliable brands/models of wall-hung, natural gas boilers in this output range? I would also like to direct-vent the unit out the side of the wall and run a DHW system off of the boiler. It would also be nice if the unit could be set up to use outside air for combustion.



--John

bob eck

take a look at triangle tube

Take a look at Triangle Tube 95% AFUE wall hung boiler vented with PVC pipe with outside air for combustion plus outdoor reset control and self cleaning stainless steel heat exchanger. These boilers do not always need to be piped primary secondary piping. with these boiler you can side wall vent or vertical vent out the roof and can bring in fresh air from a different pressure zone exhaust vent and fresh air intake do not need to be in the same location.  Prestige Excellence one size model PE110 is a 110,000 BTU input boiler with a 14 gallon stainless steel indirect water heater built in the unit and it can deliver 180 GPH (3 GPM) of domestic hot water and the domestic hot water get priority over heating. can run two showers at one time using ALSONS 1.6 GPM shower heads.  The ALSONS 1.6 GPM shower heads deliver plenty of hot water for showers.  Prestige Solo boiler only comes in 5 different sizes 60,000 - 110,000 - 175,000 - 250,000 - 399,000  pick the size for your house and use the Triangle Tube Smart stainless steel indirect water heaters in sizes 30 - 40 - 50 - 60 - 80 - 120 gallon models. these are great boilers, I have the PE110 boiler with built in water heater in for over a year and my heat and hot water bill went from $2100 with oil to under $1000 for Nat gas.

Johnny12

The TT Prestige Excellence looks nice

That TT Prestige Excellence looks like a really nice unit. I like that it has the DHW built in and has the controls on the bottom of the unit. I had seen that the Burnham Alpine could be wall-mounted, but the controls would wind up being up at the top where it was not convenient to reach them.



How are the PE110 units as far as maintenance? A condensing boiler will be something new for me, and I have read that they need more maintenance. Does the self-cleaning feature on this one work well?



Also, I see that the circulator pump is contained in the unit. Does this pump away or toward the heat exchanger?

bob eck

TT PRESTIGE BOILERS

With the Triangle Tube PE110 boiler and built in indirect water heater the expansion tank needs to be installed in the return line to the boiler. If installed in the supply line going out of the boiler when the unit starts to make domestic hot water the water in the system heats up and the three way valve is closed and the expanding hot water can not get to the expansion tank.

boiler should be looked at by a professional heating contractor every year just like a regular gas or oil boiler should be looked at ever year.

to protect yourself against expensive repairs you can buy a 5 or 10 year parts and labor warranty on the prestige boilers. If a part breaks for up to 10 years the warranty will cover replacing the defective / broken part and labor. yearly maintenance is not covered by this warranty.

I would us the Triangle tube boilers over the burnham alpine. TT heat exchanger is stainless steel and holds more water than most heat exchangers and as it condenses the condensate washes and helps keep the heat exchanger clean.

Jean-David Beyer

the energy-efficiency tax credit that expires at the end of the year is a big incentive to replace the boiler

I do not know how busy qualified contractors are in your area. Around here, I decided to replace my boiler in late 2008, but the contractor said they would be too busy with typical heating service calls at that time. I was in no rush, so they said how about in May. I said fine. They would not schedule a day until the gas company gave a date install the gas line. When that was all done, it took them all day Friday and half of Monday to do the job, that involved turning a one-zone system into two zones, and getting all the near-boiler piping replaced.



Consider that a contractor will not want to work weekends, Christmas eve day or New Years Eve day. Time is fleeting. You may already be too late.

Johnny12

Energy tax credit

I know there's a possibility that the installers will be too busy to get this done by the end of the year. In that case, I figure I can at least just purchase the boiler before the end of the year and have the install done a bit later. I'm figuring that the cost of the boiler will make the the majority of the cost anyway. I also want to purchase more insulation for the attic, so that should get me close the the credit limit.

Jean-David Beyer

From my experience as a homeowner, ...

... you should spend all the time remaining in this year to investigate and evaluate the contractors available to you to see if any of them are competent. Unles you are a contractor already qualified to do this, and have the proper tools, including a combustion analyzer, this will take quite a while. I thought I had done a good job of this until it came time for the first annual service.  The person they sent did not even know if my boiler was oil or gas. He should have been able to tell from the gas pipe going in, and the lack of an oil filter. The only thing he did was look at the fire through the inspection port. He did not know how to do a heat request to start the boiler. He did not know how to defeat the warm weather shutdown. It was obvous he knew nothing about this boiler. I showed him the relevant pages in the I&M manual, and he did not wish to read them. He said he did not have the replacement gaskets for when he opened the heat exchanger, and he had no combustion analyzer. He would not even check the pressure relief valve, the condensate drain pipe trap, or the LWCO. I sent him on his way and called up the contractor's office. The clerk who answered the phone said someone would call me back. No one did, after several attempts. I sent an e-mail and it was not answered. I sent a paper mail and that was not answered either. Once I got someone who they should not have permitted to answer the telephone. He said gas boilers did not need maintenance. I was disgusted and searched for another contractor.



The new contractor is better than the old one, but not ideal. They knew my boiler was a W-M Ultra 3; the technician came with the required gaskets and a new igniter. He even came with the correct boiler additive specified by the boiler manufacturer that the previous contractor said was unnecessary. He did not have the combustion analyzer and would not test the pressure relief valve. They do answer the telephone. I think this company can be trained by me to do a combustion test, and to test the pressure relief valve on the boiler and the P/T valve on the indirect hot water heater. But I am not quite there yet.



So by all means do the insulation. I do not know if you get credit for buying a high efficiency boiler or if it must actually be installed by year-end. And better luck at finding a qualified contractor.

Johnny12

Any opinions on Vitodens?

Any opinions on the Viessman Vitodens boilers? It looks like I would be able to get a Vitodens 100 and a tankless water heater for cheaper than the TT Prestige Excellence. Part of my thinking here is that if anything happened with the DHW heating component of the TT Prestige, it would probably be a major pain to fix, as well as a lot of $$$.

tim smith

TT boilers are great, but good installer important also

If you can find a good reliable installer in your area, I would also check to see if the local installer or supplier have parts in stock. To be honest, I never have to replace parts on them but Important to know parts are availabe. I have all parts in stock for them. Once a year, clean out condensate trap, clean flame rod/electrode. Check for air in system, top off if needed. Check expansion tank pressure, clean fill strainer, clean electronic low water cut off probe also maybe every 2 yrs. Check electical connections, fire off and check combustion with analyzer. All will be well. Good luck, Tim

Johnny12

Combustion check?

What is the purpose of the combustion check? If it's not optimal, what will the symptoms be? Increased CO? What kinds of adjustments or remedies will correct improper combustion?

Gaetano

Acoustic Pyrometer

You should use the acoustic pyrometer to obtain a real gas temperature measurament. visit www.seispain.com