Joined on February 12, 2013
Last Post on March 31, 2014
@ March 31, 2014 8:46 AM in Navien 240 combi installed - I have concernsOur setup does indeed supply three showers with newer shower heads with the CH-240 unit we have running.
Our supply line for water is much larger than yours though. We have a 3/4 supply line going directly into the unit.
We also have our unit set to the well pump setting. Not sure if that is applicable on the newer units.
@ March 18, 2014 8:35 AM in NG Combi Boiler versus indirect tank and boiler setupThe system is working fine. No issues.
@ March 17, 2014 10:27 AM in Myson 7000 toekick heaterOurs is installed as per the instructions. I believe exactly 12 inches between the monoflow Ts. Two monoflow T pointed with the arrows at each other. They are both flowing upwards.
Also have a ball valve in between the two Ts so that we can bleed the unit out easier and temporarily force the flow through it. Then once bled, open up that valve to permit flow through both areas.
And shut off valves with bleeders going to the unit itself for bypass and service purposes.
It works fine for us.
@ March 13, 2014 2:55 PM in Navien comboDid you use CPVC or PVC for exhaust?
Mine is just PVC, as per the manual when we did it.
@ March 13, 2014 2:51 PM in Navien comboYour install looks similar to mine. I just have some more pumps than you and control valves.
Mine is going good so far. What kind of maintenance do you do on yours? Filter changes, etc? And how often?
@ March 4, 2014 9:27 AM in Hydronic off new DHW for BasementYou may want to look at combi boilers. There are a bunch out there. Triangle Tube, Navien and many others.
It would accomplish what you are after and run pretty well these days.
@ February 27, 2014 8:43 AM in navien and odr?Yes, before ours was installed, I read through the entire manual myself as well. Based on the advice of another installer up in Mass who had installed many of these, he recommended we got familiar with all of the dip switches, how to hook up the thermostats, get to the hidden settings and figure out my outdoor reset curve number to input into the controller. Good thing we did, because same story here, Being familiar ahead of time we got the unit up and running quicker.
We also did a heat loss on our home to ensure we would fit in the envelope of this unit, but very few installers were willing to do so. When questioning many installers, it was curious about how many had no software to do so, and just used a simple square footage general rule of thumb. You may get away with that for a modulating unit many times, but for the cast iron traditional boilers they were recommending mostly, it would have been grossly over-sized. We even told the guys giving quotes up front we thought the old unit was way too big due to short cycling observations.
Is that normal in this industry that most installers don't size units for a home and just go bigger or the same size as what was there?
Another curious thing was that most of the guys giving quotes just wanted to install a replacement cast iron boiler and not a lighter newer modulation condensing unit. Why would an installer prefer to lug down a 900 lb boiler down into a basement versus a 100 lb wall hung unit? That confused me. Why continue to break your back if you don't need to?
Well, so far so good with our Navien. We have the CH-240 but I think there is a newer one out now. So maybe they do things differently now with the outdoor sensor on that new unit. Have to check yourself on that one. A few of our neighbors now have one as well.
@ February 3, 2014 8:10 AM in Relief Valve on NavienThe 30 PSI pressure relief valve is on the main heating loop. Mine turned out to be a expansion tank misbehaving.
Also, if you have a fast fill line and valve attached to your heating loop (i.e. city water line to bleed out the lines) on the main loop, ensure it is full closed, or the valve is not faulty. This is commonly installed as a faster way to get the air out of the lines when filling up the system loops.
@ January 9, 2014 2:19 PM in Do I really need a Navien CH-240?If you have the outside temp sensor option installed, then your outside K Curve setting may be set to aggressively for energy efficiency.
Mine is set at 1.8 in my home and kept my home very toasty warm. The setting is on the little white digital control panel hooked up to the unit. Play around with the setting a bit to see what works for you best.
The purpose of that setting is to optimize your home so that on a slightly warmer day when there is a call for heat you get an optimized slow burn at a lower loop temp. Rather then a quick on and off set of full fires that uses up more fuel. If yours is set incorrectly, your home may not heat up on the cold days due to the settings not permitting it to fully fire up.
Hope this helps.
@ January 6, 2014 10:33 AM in Combi boiler dhw and heat or dhw or heatWe have close to 4000 sq feet but with good windows. Our unit is using the outdoor temp sensor option to modulate, so it sets the loop temps itself based on need. More efficient that way.
Even during the -3 degree weather we had recently, our unit never had to work all that hard. I don't even think our loop temps went over 160 and we kept the house at an even 72. It was a good test to see how the unit would do in extreme weather for our home.
Do you have a picture of how your unit is installed?
@ January 6, 2014 8:52 AM in Combi boiler dhw and heat or dhw or heatWe set our family's unit to 130. There was a way to get into the special settings to override that to get above 120. Works well at that temp.
Also, we set ours to the well water setting. Our installer said it works better on that setting for most people.
@ December 30, 2013 1:18 PM in Need help with boiler replacement and DHW issueHenry, we are pretty close to your stated number with our unit. 240 KTBU is the size of our unit. The large output was needed for hot water, like you said.
Otherwise when running heat, much lower. Impressive stuff with these mod cons these days, compared to our old cast iron unit. Fuel bills are drastically lower.
Also, hot water taking priority really has not been a big deal in real life in our home. We don't even really notice it to be honest.
Hope this helps. Interesting and cool stuff to look into nonetheless. It is nice to have options for people with tight budgets, like ourselves.
@ December 30, 2013 1:03 PM in Need help with boiler replacement and DHW issueYou know your stuff.
We live in a moderately cold climate in Philadelphia area. Not subarctic conditions, but get a good cold winter with about a 4 degree design day.
We spent a lot of time deciding our unit to make sure about the hot water demands.
You are correct, we have a 3/4 line for our larger soaker tub, otherwise it would take an eon to fill it. Any good plumber would probably make sure the lines are sized correctly if possible.
We have everything you mentioned and the larger combis these days can do it. We ruled out the triangle tube Prestige for that very reason, its flow rates on hot water were too low. Although it has an excellent reputation in the industry. We have about the same heat loss as this person's home.
We deliver enough flow in the dead of winter to satisfy a few showers at 130 degrees in our climate. Take a look at the large combi options, you may be surprised how far they have come in the last few years. Navien is just one, but there are others now coming to market in the same larger sizes with 10 to 1 turn down ratios.
We are very happy we decided our combi. Many of the installers coming out for quotes told us it was not possible. They can indeed do it now. Otherwise, if one unit can't deliver enough hot water, many of these units these days can be cascaded to work jointly with each other. Still cheaper and simpler to install two of them in many cases than other options.
@ December 27, 2013 2:14 PM in Need help with boiler replacement and DHW issueThere are larger combis out there that sound like they would meet his hot water demands just fine.
Why add the expense and complications if one unit can handle it all with nearly the same efficiency?
@ December 27, 2013 2:00 PM in Need help with boiler replacement and DHW issueNavien, Triangle Tube and others make them and would certainly be a very cost-effective and efficient option to consider.
We have a Navien CH-240 in our home with a similar heat loss to what you stated. (90KBTU seems a bit low for a home that large though). I believe many of them can be cascaded as well.
We service three full baths and almost 4k square feet and the thing never really has to full fire even on the cold days.
They have a newer model out right now that appears to have a 1/2" gas line connection and smaller PVC exhaust pipe and better efficiency.
The way to size the combi's from what we learned from people here and our installer is first by hot water demands, then heat. Example, on the coldest day of the year the unit does about 5 gpm of hot water and 8.5 during a summer day. Figure about 1.8 gpm per shower head on newer homes and gives you about 2 to 3 showers possibly at the same time at full pressure. Otherwise, you still get hot water but lose some pressure. We have a whirlpool bath, and this thing works fine for us. Also, hot water usually takes priority, so went you call for hot water, your heating of the home is temporarily stopped. It is really not an issue unless you plan on using how water continuously all the time, like a car wash business.
For the heating side, you then see if the output BTU's will fit your heating needs. Sounds like it may be an option based on your old boiler size. Another example, the turn down ratio is 10 to 1 on a mod con boiler. So, with the external temp sensor for the modulation feature, the unit can do a slower burn and be more efficient lowering the temp outputted to run longer, slower and cooler and somewhat coldish days. Then on cold days, it would run hotter. This modulation helps give a little more wiggle room in sizing as well, as the unit can dynamically figure out heating demands based on sensor and program region temperature curve inputs into the computer.
This would probably be your cheapest option.
Otherwise a mod con boiler and indirect tank may be a second option, but considerably more expensive.
You will see a lot of negative feedback on combis on this forum from some folks. But, I own one, know others than own one, and they work. If you go this route, just find someone that has done them prior, as they need to be installed correctly (primary/ secondary loops, pump placement/ direction, etc.)
@ December 19, 2013 1:44 PM in Combi boiler dhw and heat or dhw or heatWe own the same unit. Your hot water will take priority over heat.
We set our hot water temp to 130, as it compares more to our previous hot water system at that temp.
Also, we set ours up for the well water setting.
How has yours been going? How big is the home and how many baths? Our experience has been very positive so far.
@ December 13, 2013 9:08 AM in boilerIf you want to clean the power, then a good UPS will do that. You will need to calculate the max power load and size accordingly.
It will also protect against brown outs (partial losses of power) at a minimum, and a short power outage.
It will also provide surge protection.
If you have those concerns, this is the best route to go.
If you want long power outage protection times, then you can add a backup generator as well. A UPS is still not a bad thing to have even then to clean the power.
Good luck and hope this helps.
@ December 11, 2013 10:48 AM in boilerStaples or any office supply store will have them. An inexpensive APC or other brand backup battery UPC will do a few things. It will clean the power, provide surge protection, protect against brown outs and provide a short battery backup window.
Some of them even allow you to log to power conditions, graph and log power issues. You can maybe use this to submit to your utilities commission in your state to get the power company to ultimately fix your issue to avoid the hassle going forward.
There are different ratings on them. Just make sure you get one with enough capacity for your power demands. In this case, bigger is typically better.
@ December 9, 2013 10:25 AM in Navien ch 240My home is that big and it works just fine.
@ December 5, 2013 10:16 AM in Navien ch 240Argue your point with Navien then and let us know please.
@ December 4, 2013 4:57 PM in Navien ch 240I own one.
The large BTU capacity is to meet hot water side demands for about two to three showers at the same time before losing some pressure.
The heating side heats my large home just fine.
It is efficient.
Just took a look at their website. It appears the newer model has an updated burner that accepts a 1/2 gas line, rather than 3/4. Also, the vent pipe appears smaller. It also has higher overall combined efficiency ratings. The hot water side in a combi will drag the overall combined efficiency rating down.
It puts out more than 50KBTU when installed properly to primary and secondary loops. The previous poster was incorrect, as it is proven by real life operations in my home.
@ November 22, 2013 3:58 PM in Boiler optionsA combi boiler is an option.
Triangle Tube, Navien, etc.
You can run PVC right up the existing chimey and run off Propane versions.
I have one in a bigger home and it runs well with a Navien. Plus it is less expensive for some models and less infrastructure to maintain.