Lochinvar KHB199N Install & boiler pump alternative

henry10583

Hi all,

I've been on this forum since last year (Nov 2022) after I had to have our 12 year old Peerless Purefire modcon replaced around Thanksgiving due to a compromised heat exchanger.

Prior to replacing the Peerless, I didn't really know anything about boilers as the home and boiler were both new-to-me in 2021.

On the recommendation of our plumber, we installed a Lochinvar KHB199N to replace the Peerless Purefire PF-210N that the house came with. The plumber who replaced the boiler didn't do any heat loss calculations and I didn't know any better to ask for such at the time -- he went for a like-for-like replacement size wise, even though subsequent Manual J calculations have shown that we could have probably gotten by just fine with a KHB155N (5.5k sqft house, 3 levels, 4 zones one for each level & garage baseboard, lots of windows but peak load of ~70k-80k BTU/hr on design day for suburban NY).

Space heating for the main and upper level zones are via forced air (air handlers & hydrocoils). The finished basement has baseboard heating, although its rarely required due to ducting shared with the main level supplying it heat. The garage has a small stretch of baseboard which is rarely used except to keep the garage above freezing in the winter.

Finally, the boiler also powers a 80 gallon Heat Flo indirect water tank (at 130 deg F, mixed down to 115 deg F past a mixing valve) on the other side of the room and is supplied by a Taco 0014 circulator for the DHW secondary loop (boiler_1 image attached). The DWH zone is prioritized and can only take ~120k BTU output from the Lochinvar via the 1" copper zone piping (all the piping is original to the house which was built in the early 2010's).

Post install, I had a lot of problems with the Lochinvar that, thanks to this forum, I have largely been able to address since. The installer left the install site with a boiler blowing natural gas past a leaking supply pipe (i.e. didn't do a basic gas leak test), failed to do a combustion analysis, had the boiler set at 180 deg F supply temp with no outdoor reset, the boiler wailed like a foghorn and the DWH zone was not wired in to support being prioritized. The list of ailments is longer but I'll spare the thread. Needless to say, the installing company is no longer welcome at my house and it's shocking that companies like that can remain in business putting their customer's at risk.

With the context set, onto my question. In addition to the ailments listed above, the installer effectively "stole" the factory-supplied Grundfos UPMXL 25-124 boiler pump and left in the original Taco 011 that was original to the Peerless boiler install (12+ years and going). The Grundfos is a variable speed 0-10V circulator pump and the Taco 011, while a good pump, is decidedly not variable speed. Here's a link to what Lochinvar recommends:

https://www.lochinvar.com/lit/866204PUMP-KHBWHB-Rec-02.pdf

I would like to make the most of the Lochinvar "smarts" by installing a variable speed boiler pump so that my delta T, especially when the boiler is modulated < 50%, can be in the 20+ degree range (right now, at 10% downfiring I'm lucky to see a few degrees delta T, which by my understanding suggests we may be overpumped on the primary circuit?).

Am I going along the right path with thinking about replacing the Taco 011 with a variable speed circulator that can be controlled by the Lochinvar's 0-10V boiler pump outlet?

If I wanted to keep everything Taco, is there a Taco equivalent to the Grundfos UPMXL 25-124 that I should have my (new) HVAC contractor look into?

I was thinking that while we were at the back of the boiler replacing the boiler pump, my contractor could also look to fix the intake and flue venting, but I'll let The Wall decide/comment on if there's anything to be gained by modifying the venting.

All pictures are attached. Thank you for your time and great content on here that have helped me become a more informed and responsible homeowner!

hot_rod

yes the boiler will benefit from the v/s pump
The outdoor reset should be enabled also 

I think that Grundfos is specific to Lochinvar, an OEM pump, so it may have a unique algorithm. Check with a Lochinvar rep, or their tech support 

Can you get the pump from the contractor?
Its not an inexpensive size pump🫢

henry10583

@hot_rod thank you for your comment! Just wanted to quickly say, I've learnt so much from your posts and comments over the past year

RE: VS pump from Grundfos, I'll check with Lochinvar in the morning and see what they say.

RE: the outdoor reset, I got a Tekmar 087 installed a few months ago and that seems to be working great and allows the sensor to be placed in the optimal orientation on the side of the house while still being in range of the receiver:

https://www.supplyhouse.com/sh/control/product/~product_id=087

RE: contractor giving me the Grundfos OEM pump I paid for with the purchase of the new boiler -- unfortunately that ship sailed. The boiler was installed a year ago and dealing with the plumbing company owner at that time to come back and fix the gas leak (which failed inspection) and the lack of combustion testing/calibration is an experience I would happily pay to never have to go through again. An expensive mistake, but life's too short to deal with such toxicity. Karma usually has a habit of finding its way to where it needs to go in the universe in any case, so I'll just move on and let it be. For anyone reading this in the future, it's been said many times on here before, but the installing contractor is way more important than the equipment itself in the grand scheme of things. I learnt this lesson the hard way for sure on this occasion.

@hot_rod while I have you here, what are your thoughts on the intake pipe? From what I've seen and read, the "foghorning" may be from resonance coming from the intake pipe. Most if not all Lochinvar installs I've seen have shown the intake pipe going straight up from the 90 coming out of the boiler, but mine is so constricted its almost doubled back on itself on a 180 degree turn. In your experience with Lochinvars, is it better to go straight up for a few feet coming off the boiler connection 90?

GroundUp

I can't open the photos, but foghorning in a Lochinvar is often due to poor combustion. Has the boiler ever been tuned with an analyzer? Is there a specific firing rate at which it's most prevalent? Is the gas piped in CSST by any chance? If you want to eliminate the intake from the equation, loosen the clamp and pull the intake apart so it's drawing room air

hot_rod

The vent table in the manual tells you how many ells and feet of pipe you are allowed. Good that it is 3"

An ell and a 45 count as so many feet of straight pipe. So add the fittings and all the piping to see how it matches the vent table.

How are they terminated? thru the roof? separated by 12" or more? Vent caps or at least bug screens?

henry10583

GroundUp said:

I can't open the photos, but foghorning in a Lochinvar is often due to poor combustion. Has the boiler ever been tuned with an analyzer? Is there a specific firing rate at which it's most prevalent? Is the gas piped in CSST by any chance? If you want to eliminate the intake from the equation, loosen the clamp and pull the intake apart so it's drawing room air

@GroundUp Thank you for your message. Apologies for the issues with the photos not displaying, I'll try re-adding a few relevant ones below:




The boiler was "dialed in" using a combustion analyzer and the service tech needed to adjust the gas valve too to get the numbers in range. Looking at the slips again, I'm not sure I'd entirely trust the number if the Testo calibration/service date is accurate. The work was done in 2022, at which point the combustion analyzer had been in use for several years without calibration or service.

RE. there being a specific firing rate where the issue is prevalent, when the boiler starts up it whines like an old supercharger on a car engine, goes to 61% then whines some more before falling to 10% firing. The worst harmonics happen at 10% and ~45% then again at 75%. For context, the Peerless was virtually silent, but I detect two sounds that are particularly unpleasant with the Lochinvar (1) fan/Venturi whining when starting and when firing (2) panpipe like harmonic from the pipe which, from what I've read elsewhere on here, may be fixed by putting a small hole in one of the intake elbows.

RE. gas piping, no CSST, just black iron pipe, 3/4" down to 1/2" at the boiler side.

RE: pulling the clamp and allowing the boiler to draw room air: I'd love to give that a go, but was concerned with possibly altering the combustion ratios by introducing potentially too much O2 and leaning out the fuel/air ratio too much or am I overthinking it? My mechnical room has a "fan in a can" I can turn on to draw in outside air into the space to provide makeup air. If indeed removing the intake pipe fixes the harmonics issue, is there any downside to leaving the boiler pulling intake air from the mechanical room for an extended period of time until a contractor is able to repipe the intake an vent?

henry10583

hot_rod said:

The vent table in the manual tells you how many ells and feet of pipe you are allowed. Good that it is 3"

An ell and a 45 count as so many feet of straight pipe. So add the fittings and all the piping to see how it matches the vent table.

How are they terminated? thru the roof? separated by 12" or more? Vent caps or at least bug screens?

@hot_rod Thank you for your message.

RE: vent length: by my math we're at about ~44ft of intake, accounting for

3x90s (21ft equivalent)
3x45s (12ft equivalent)

7 feet to mechanical room ceiling
4 feet off mechanical room ceiling to intake pipe (black cover in picture below)

The Lochinvar manual states a maximum length of 100ft for the air intake for 3" pipe so I believe we should be ok on that front.



The intake (bottom black Lochinvar bird screen 3" pipe at the bottom of the pic) and the exhaust vent (white pipe ~12" above) are both protected by bug/bird screens. As seen in the picture above, the pipes come up through the mechanical room ceiling and through the side wall

tim smith

I expect it is fog horning on low fire. I might want to get high fire co2 up a bit and low fire down at the lower scale. Some times tweaking around gets the fog horn to go away. Just takes some messing around. Other thing to do is get a lochinvar 3" silencer installed, they can be fairly noise at intake outside especially on high fire, the silencer does great to reduce that. Just fyi.
Tim

GroundUp

The high fire is pretty lean, I've had success with running the CO2 on the high end of the spectrum (10.5% for that boiler on natural gas) to eliminate foghorning. The low fire could use the same treatment, though not as drastic (9.5%). Regarding the intake, there should be no issue with sucking room air as long as you have enough makeup air to the room. It will be louder than it is now as you'll hear the intake sucking air, but if it eliminates the issue, you have a good handle on what needs to be done. When the technician "tuned" this unit, was he just ignoring the foghorning or did that come later on? Does it make a "whoof" sound when it fires up?

henry10583

GroundUp said:

The high fire is pretty lean, I've had success with running the CO2 on the high end of the spectrum (10.5% for that boiler on natural gas) to eliminate foghorning. The low fire could use the same treatment, though not as drastic (9.5%). Regarding the intake, there should be no issue with sucking room air as long as you have enough makeup air to the room. It will be louder than it is now as you'll hear the intake sucking air, but if it eliminates the issue, you have a good handle on what needs to be done. When the technician "tuned" this unit, was he just ignoring the foghorning or did that come later on? Does it make a "whoof" sound when it fires up?

Thank you @tim smith and @GroundUp for your insights! Very helpful and is leading me towards revisiting the combustion tuning of the boiler.

@GroundUp RE: "When the technician "tuned" this unit, was he just ignoring the foghorning or did that come later on?" the technician was called back because of the foghorning in fact. At the time, the boiler would wail even lounder (think 85db+ wall shaking) and short cycle constantly. I was able to address the short cycling by reading the manual and setting up the anti cycle ramp delays. The foghorning, however improved with some light "tuning", has somewhat remained. The "technician" left the visit stating that boilers this large are all this noisy and that he'd tuned it within spec, nothing else to be done...

RE: "Does it make a "whoof" sound when it fires up?" yes, it makes a loud "whoof" on startup then whines as its firing ramps. Worst resonance/whine is at 10%/~45%/78%. I have the boiler capped at ~60% to not overpower the indirect and on ODR with a max water temp of 130 deg C, so it now pretty much won't ramp to anywhere near to 100% (again, v. oversized).

Is the "whoof" sound on fire up characteristic of a particular issue I should be aware of?

Also, I'm picking up a Grundfos UPMXL 25-124 on Friday that should have been installed when this was new. I'll hopefully get that installed soon. The Lochinvar part for this replacement pump is 100304110 if that helps anyone in the future.

hot_rod

The local factory rep or Lochinvar factory tech support on the phone can often help a service person fine tube the noise away. Get deeper into gas valve settings that the manual does not cover.
It should be silent across the firing range, and no whoof on start.

Also the Ramp Delay and firing limit I think only effects the heating mode.
There are different setting for indirect DHW temperature range. Page 22 of the Service Manual
If the indirect is piped as such, give it full boiler output to recover.

Also the setpoint for the variable speed circ, when you get it, is adjustable from 18- 60°, default is 20°.

This is one of the most adjustable boilers out there. If you have time read and re-read the manual and play around with all the parameter options to fine tune this to your systems needs.

Use the back page of the manual to keep track of the settings you apply, so you remember which you tweaked.

Write it on the boiler or remember the Tommy Tutone 5309 access number

GroundUp

Thank you. I'd be pretty confident, based on your information, that this could be largely if not completely worked out by adjusting the CO2 toward the top end of the range as mentioned earlier- both in high and low fire. Gas pressure may be another conflict, it'd be great to know what the incoming pressure is at the gas valve both before and during startup. These units like a little higher gas pressure than most others do, and it should not drop more than 1" of pressure while starting up.