Alpine 105 Sage 2 Controller replaced

Slowhand63 · January 14

yes, there’s a modulation s/u screen. The available variables are set as follows:

- min 1250 rpm

- max DHW 4000

- max central heat 4850 rpm

I read the instructions for the mixing valve and also expected to see 110 deg. I thought maybe since the radiant wasn’t calling for heat that the manifolds drifted to room temp, but in hindsight that’s probably not logical if the (bathrooms) were warm.

hot_rod · January 14

so my questions would be

Why is there a mixing valve?

Is the mixing valve running ODR and the boiler running ODR?

It looks like 5 loops of pex, is that the total heating load on the boiler?

If so 5x .5 gpm per loop is 2.5 gpm, or approximately a 25,000 btu/ hr load connected

It that is the case you would want to derate the boiler from 105, down to max 25,000 if that is possible. Most mod cons are 10-1 turndown, so yours should modulate down to 15,000 btu/hr

We need to make sure the version of the control and the manual match up.

Is the new control you installed a newer version?

I would want to make sure we have the correct manual and then determine what parameters are available for you to access.

Some boiler controls need a password to access installer programming, which opens more options. My Lochinvar has a User and Installer access. Not much programming is available in User mode.

probably call a U.S. Boiler rep to answer that and if the zone controller needs to be connected to open the parameter #10 that I showed above

Slowhand63 · January 14

I can’t answer why there’s a mixing valve. I didn’t design the system. I thought the general use of the valve was to improve efficiency of the system. Given the cost of the valve ($500+) I’d be surprised if it was installed but not needed (but you never know…).

There are four radiant loops Two operate with a single thermostat (kitchen - hardwood floor) and 1 each for two bathrooms. The boiler is also used for the indirect HW tank. The installer sized the boiler for up to 8 zones (manifolds are 8 zones) for future expansion (house has 5 bathrooms).

The Sage controller that was failing was a 2.1 I installed a 2.3. The 2.1 was not the original that came with the boiler.

I’ll have to investigate the ODR and report back tomorrow.

When adjusting parameters I need to log in with the contractor passcode. User access is “read only”.

Since I’ve been round and round through the screens I can access, I’m guessing that the lack of a zone controller is why I cant access parameter 10.

hot_rod · January 14

I have a call in to a U.S. boiler rep that I know. I’ll see what he can clear up

Maybe you need the Heat Match software to access some settings?

You would pick up some efficiency by piping without the mix valve and let the boiler modulate on ODR and the step fire function. But that would take some repiping

IMG_1793.jpeg

hot_rod · January 14

Eastman · January 14

You’re not looking for a “parameter 10”. That was a section heading in the boiler manual. The original settings sheet you wrote out includes a “Modulation Setup”. Look there.

Typically a mix valve would not be used unless you wanted to run two temperatures: one for the hardwood and maybe another for tile. But the would require some modifications of the piping. Maybe originally this was expected, but then the plans changed?

Check to see if you have an outdoor temperature sensor connected to the boiler. It’s better to disable the mix valve and use the boiler settings for temperature control directly in this case.

Slowhand63 · January 14

I’ve already described all of the adjustable parameters in the modulation s/u section. There are 3:

- min (1250 RPM)

- max DHW (4000 RPM)
- max Central Heat (4850 RPM)

That’s all I can access from the front panel of the Alpine. I’m using the password protected “adjust” access to look through the software settings.

I checked this morning - yes, outdoor temp sensor installed. It is wired to BOTH the mixing valve and the boiler. If needed I can detail the wiring (it’s a bit of a jumble of low voltage wiring twisted together). There’s also a wire that runs from the mixing valve to a union, that I’m guessing is a thermocouple? It’s placed immediately after the circulator for the radiant.

When the system was installed only 1 bathroom had been piped for radiant, with future zones TBD.

hot_rod · January 14

I would adjust the max rpm down until it reads around 30,000 btu/hr, I don't know what rpm that will be.

The boiler and the I-valve would need to have individual sensors mounted outside, on a north wall, they could not share a sensor.

I'm not sure how two outdoor reset control behave with one another. I would prefer the boiler adjusts based on ODR, if saving fuel and increasing efficiency is the goal.

I could be the i-valve is targeting one temperature, the boiler another temperature, based on how the two are adjusted?

Slowhand63 · January 14

I’m reluctant to start adjusting the RPM down without a clear understanding of how it will impact the boilers operation. If I begin to lower it, what changes should I expect to see? How would I know when I’ve gotten to the optimal setting? How would I know when I’ve gone too low? I feel like I’m flying in the fog with no radar.

hot_rod · January 14

You would either want to know the heatload of the building and adjust the boiler output to that.

Or just try a few different settings.

An analogy, how far down do you depress you accelerator when driving? The same for the boiler, lowering the RPM, lowers the horsepower.

You wouldn't floor your accelerator and use the brakes to control your speed??

So running the boiler to full power for a load that is a fraction of the HP wastes fuel, shortens component life, is annoying to hear it going on and off every 8 minutes, etc.

There is no exact answer, my suggestion is limit the heating output of the boiler to 50%. Does the home maintain temperature on a cold day r night. If so lower it another 5%

The manufacturer puts all those settings and parameters in the control so the user or installer can adjust the boiler to the specific job. You paid for them, may as well use them.

Slowhand63 · January 14

I thought I’d trace out the low voltage mixing valve wiring to better understand how everything operates. I found what is likely an issue.

The valve has two strap on sensors (Taco 9300-2044) that I’ll ignore.

The outdoor sensor has two conductors: one Green (G) and one Blue (B).

The G is connected (wire nut) to a Red ® wire that runs to the mixing valve. Let’s call this wire nut “N” and I’ll come back to it in a minute.

The B also runs to the mixing valve (wire nut - white (W) wire to the valve) and also has a B wire that goes to a terminal strip of the boiler. The terminal strip is immediately behind the front panel of the pull out tray to the far right. The terminal strip connection location says “DHW sensor/outdoor sensor).

There’s also a G wire connected to the location of the terminal strip immediately below the B wire. The term strip label says “outdoor sensor”. This G wire runs back to the wire nut N mentioned above where the G outdoor sensor wire and R mixing valve wire are connected. It’s stripped and looks like it might have popped out of the wire nut.

The other wire nut (the B-B-W) connection is very close by, but the position of the green wire (and color) tells me it should be connected to “N”.

I should also mention that there are lots of other stripped wires just twisted back and not connected to anything as the cable was 4 conductor with only 2 conductors used.

I’m thinking I’ll power the unit down, connect the green wire @ “N” and power back up.

Make sense?

Slowhand63 · January 14

correction: location of the power strip is behind the pull out tray in the LEFT corner.

hot_rod · January 14

If it were me I pull the actuator of the mixing valve, move it to full open. Assure the boiler ODR is connected and working and let the boiler do the thinking. I think you have 2 conflicting controls at work.

Spend your time and energy on getting the boiler parameters dialed in. There should be an outdoor sensor.

Even if you ball up a setting there is probably a "return to factory setting" overide that takes you back to square 1.

Running a mod con to 150 to mix it down to 110 for the radiant makes no sense at all. To me anyways.

Unless there is a zone that requires 150 supply temperature?

The Alpine outdoor sensors look like this.

You might check US boiler website or search You Tube for a U S Boiler Sage 2.3 programming video.

Eastman · January 14

@Slowhand63 Regarding the outdoor sensor wiring:

The sensor is a 10Kohm thermistor. It is a variable resistor that changes it's resistance depending on the temperature. I am not an electronics guru, but I advise you to only connect it to the mix valve, or to the boiler. But not both. Here is my reasoning. Inside both the mix valve and boiler, there is an electronic system that needs to determine the resistance through the outdoor thermistor sensor. There are different ways this can be accomplished. I do not know how the mix valve does it. And I do not know how the boiler does it. It is quite possible the two methods will interfere with each other or even damage each other. Perhaps someone that knows more about these electronic systems will comment.

@hot_rod wants to skip ahead.

Disconnect the sensor from the mix valve and wire it into the Alpine instead. (They both use 10kohm thermistors.) The boiler will be aware of the connected sensor and you should be able to see the current outdoor temperature in one of the details screens.

The mix valve should be configured as hot_rod described above.

Slowhand63 · 1:23AM

Thanks to both of you for the suggestions. My plan will be to disconnect the low voltage wiring from the mixing valve, connect the outdoor sensor to the Alpine, and see what it tells me. After a bit I’ll begin to reduce the RPM on the Central Heat from 4850 - first to 4000, then to 3600 and then 3200. I’ll report what I see as I go.

Re setting the mixing valve in the fully open position - I’ll have to research how to do that. I assume I can turn the large black dial on the actuator clockwise until it stops?

I have to travel for work and won’t be back until Tuesday or Wednesday. Unfortunately I’ll need to wait to then until I make the above changes. Hopefully you’ll both be able to re-engage once I have some additional information. I really appreciate all of the guidance to this point.

Eastman · 2:00AM

That's fine. You have the right idea now.

I don't know why they put a mix valve in the system. Maybe they were worried about the wood floors expanding and contracting as the boiler cycles on and off? It would make sense if you had a more traditional high mass boiler. But a modcon like yours should regulate well enough by itself for this application, I would think.

hot_rod · 2:02AM

I think with power disconnected from the mix valve you can manually turn it to hot. I think it is basically a 3 way ball valve with a motor actuator.

Alpine 105 Sage 2 Controller replaced

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