Hayward Omnilogic Temperature Not Changing

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 2, 2025

• Add bookmark
• #21

Hold on for a second.

 

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 2, 2025

• Add bookmark
• #22

I think that the values for DC volts are for ProLogic (5 volts unconnected).

It looks like Hayward changed to 3.3 volts DC for OmniLogic temperature Sensors unconnected, so the 3.28 looks like it might be correct.

The resistance values are still the same, but the DC volts will be different for each temp.

We would need to find the chart for OmniLogic to see the other numbers.

You can get a few different resistors and connect them in place of the sensor to see if the temp reads correctly.

For example, a 10k ohm resistor should read 77 degrees.

A 7k ohm resistor should read 92 degrees.

17k ohms is 56 degrees (10k and 7 k in series).

4,118 ohms should read 115 degrees.

A 10,000 ohm resistor in parallel with a 7,000 ohm resistor results in an equivalent resistance of approximately 4,118 ohms.

To calculate the equivalent resistance of two resistors in parallel, use the formula: 1/R_total = (1/R1) + (1/R2).

1/x = (1/10000) + (1/7000).

X = 4,118 ohms.

 

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 2, 2025

• Add bookmark
• #23

davidl81 said:

Also all three probes read right at 10,300 on the resistance when connected.

Click to expand...

You can't test resistance when the sensors are connected because the voltage will interfere in the test.

Even though we do not know the exact DC voltages for each temp, we know that they should be different for each temp.

If you connect the different sensors are they all reading the same DC voltage and the same temp even though they are at different temperatures?

Get some warm water in a cup and some cold water and put the temp sensor in the water while the sensor wires are connected to see if the temp reading changes.

What happens if you connect the Solar temp sensor to the Pool or Air Temp sensor location?

 

Last edited: Mar 2, 2025

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 2, 2025

• Add bookmark
• #24

 

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 2, 2025

• Add bookmark
• #25

For this chart based on 5 volts DC, we can use this formula for V_R = 5.0(R/(R + 10000)).

R = 10000V_R/(5.0 - V_R)

If we assume a 10k ohm internal resistance for the ohmmeter, we can use this formula.

V_R = 3.3(R/(R + 10000))

R = 10000V_R/(3.3 - V_R)

1.77 volts DC = 3.3(R/(R + 10000)).

R = 10000(1.77)/(3.3 - 1.77)

R = 11,569 ohms = 71 degrees.

 

Last edited: Mar 2, 2025

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 2, 2025

• Add bookmark
• #26

Voltage vs. Resistance Chart (1000 ohm increments) For OmniLogic at 3.3 volts.​

Using the formula: V = 3.3(R/(R + 10000))

Claude Artifact

Try out Artifacts created by Claude users

claude.site

Resistance (Ω)	Voltage (V)
1,600	0.47
2,600	0.72
3,600	0.90
4,600	1.04
5,600	1.16
6,600	1.26
7,600	1.35
8,600	1.43
9,600	1.50
10,600	1.69
11,600	1.75
12,600	1.80
13,600	1.85
14,600	1.90
15,600	2.01
16,600	2.04
17,600	2.08
18,600	2.11
19,600	2.13
20,600	2.21
21,600	2.24
22,600	2.26
23,600	2.29
24,600	2.31
25,600	2.33
26,600	2.35
27,600	2.37
28,600	2.39
29,600	2.48
30,600	2.50
31,600	2.52
32,600	2.53
33,600	2.55
34,600	2.57
35,600	2.58
36,600	2.59
37,600	2.61
38,600	2.63
39,600	2.64
40,600	2.65
41,600	2.66
42,600	2.67
43,600	2.68
44,600	2.70
45,600	2.71
46,600	2.72
47,600	2.73
48,600	2.74
49,600	2.75
50,600	2.76
51,600	2.77
52,600	2.77
53,600	2.78
54,600	2.79
55,600	2.80
56,600	2.80
57,600	2.81
58,600	2.82
59,600	2.83
60,600	2.84
61,600	2.85
62,600	2.86
63,600	2.87
64,600	2.87
65,600	2.88
66,600	2.89
67,600	2.89
68,600	2.90
69,600	2.90
70,600	2.91
71,600	2.91
72,600	2.92
73,600	2.92
74,600	2.93
75,600	2.93
76,600	2.94
77,600	2.94
78,600	2.94
79,600	2.95
80,600	2.95
81,600	2.95
82,600	2.96
83,000	2.96

 

D

davidl81

0

Oct 8, 2018

31

HUMBLE, TX

• Mar 2, 2025

• Add bookmark
• #27

JamesW said:

With the plugs disconnected, test for DC Voltage from red dot to green dot on the three Comm Buss pins.

View attachment 630444

Click to expand...

5.5V

 

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 2, 2025

• Add bookmark
• #28

 

Last edited: Mar 2, 2025

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 2, 2025

• Add bookmark
• #29

See if these values line up with volts, temp and resistance for your system.

For example, 1.77 volts DC connected should be correct for a resistance of 11,589 ohms and a temp of 71 degrees.

Try the resistors to verify.

 

Last edited: Mar 2, 2025

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 2, 2025

• Add bookmark
• #30

davidl81 said:

All three terminals measure right at 3.28V with the probes disconnected, and 1.77V with the probes connected.

Click to expand...

Assuming the same internal resistance of the ohmmeter, we can correct the voltage by multiplying by 5/3.3 or 1.51515.

1.77 VDC x 5/3 = 2.68 VDC.

 

D

davidl81

0

Oct 8, 2018

31

HUMBLE, TX

• Mar 2, 2025

• Add bookmark
• #31

JamesW said:

Assuming the same internal resistance of the ohmmeter, we can correct the voltage by multiplying by 5/3.3 or 1.51515.

1.77 VDC x 5/3 = 2.68 VDC.

View attachment 630496

Click to expand...

Actual pool temp is 72 right now (from my Apple Watch), so it somewhat seems like the voltage readings match the actual temp. Yet the OmniLogic displays something different. I’ll try the hot water into the air temperature sensor in a little while, getting caught up with other family stuff right now.

 

• 

Reactions: JamesW

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 2, 2025

• Add bookmark
• #32

Claude Artifact

Try out Artifacts created by Claude users

claude.site

Claude Artifact

Try out Artifacts created by Claude users

claude.site

Air/Water Sensors: Modified Resistance Chart​

Use the following chart to determine the reported temperature of a sensor based on either resistance (with sensor disconnected) or DC voltage (with sensor connected):

F°	Ohms	Volts	F°	Ohms	Volts	F°	Ohms	Volts	F°	Ohms	Volts	F°	Ohms	Volts	F°	Ohms	Volts	F°	Ohms	Volts
1	82,719	2.94	21	44,879	2.70	41	25,391	2.37	61	14,921	1.97	81	9,076	1.57	101	5,697	1.19	121	3,679	0.88
2	80,142	2.94	22	43,577	2.69	42	24,704	2.35	62	14,543	1.95	82	8,861	1.55	102	5,570	1.18	122	3,602	0.87
3	77,656	2.92	23	42,318	2.67	43	24,037	2.33	63	14,176	1.93	83	8,651	1.53	103	5,446	1.16	123	3,527	0.86
4	75,255	2.91	24	41,099	2.65	44	23,391	2.31	64	13,820	1.91	84	8,447	1.51	104	5,326	1.15	124	3,454	0.84
5	72,937	2.90	25	39,919	2.64	45	22,764	2.29	65	13,473	1.89	85	8,249	1.49	105	5,208	1.13	125	3,382	0.83
6	70,698	2.89	26	38,777	2.62	46	22,156	2.28	66	13,136	1.87	86	8,056	1.47	106	5,094	1.12	126	3,312	0.82
7	68,535	2.88	27	37,671	2.61	47	21,566	2.26	67	12,809	1.85	87	7,867	1.45	107	4,982	1.10	127	3,244	0.81
8	66,447	2.87	28	36,601	2.59	48	20,993	2.24	68	12,491	1.83	88	7,684	1.43	108	4,873	1.08	128	3,177	0.80
9	64,428	2.86	29	35,565	2.57	49	20,438	2.22	69	12,182	1.82	89	7,506	1.41	109	4,767	1.06	129	3,112	0.79
10	62,479	2.84	30	34,561	2.56	50	19,900	2.20	70	11,882	1.80	90	7,333	1.40	110	4,664	1.05	130	3,049	0.77
11	60,595	2.83	31	33,590	2.54	51	19,377	2.18	71	11,589	1.77	91	7,164	1.38	111	4,563	1.04	131	2,987	0.76
12	58,774	2.82	32	32,648	2.53	52	18,870	2.16	72	11,305	1.75	92	6,999	1.36	112	4,464	1.02	132	2,926	0.75
13	57,014	2.81	33	31,737	2.51	53	18,377	2.14	73	11,029	1.73	93	6,839	1.34	113	4,368	1.00	133	2,867	0.73
14	55,313	2.79	34	30,853	2.49	54	17,899	2.12	74	10,761	1.71	94	6,683	1.32	114	4,274	0.99	134	2,809	0.73
15	53,669	2.78	35	29,998	2.48	55	17,435	2.10	75	10,500	1.69	95	6,530	1.31	115	4,183	0.97	135	2,752	0.71
16	52,078	2.77	36	29,169	2.46	56	16,985	2.08	76	10,246	1.67	96	6,382	1.29	116	4,094	0.96	136	2,697	0.70
17	50,541	2.75	37	28,365	2.44	57	16,548	2.06	77	9,999	1.65	97	6,238	1.27	117	4,007	0.94	137	2,643	0.69
18	49,054	2.74	38	27,587	2.42	58	16,123	2.04	78	9,758	1.63	98	6,097	1.25	118	3,922	0.93	138	2,591	0.68
19	47,616	2.73	39	26,832	2.40	59	15,711	2.02	79	9,525	1.61	99	5,960	1.23	119	3,839	0.92	139	2,539	0.67
20	46,225	2.71	40	26,100	2.38	60	15,310	1.99	80	9,297	1.59	100	5,827	1.21	120	3,758	0.90	140	2,489	0.66

F°	Ohms	Volts	F°	Ohms	Volts	F°	Ohms	Volts	F°	Ohms	Volts	F°	Ohms	Volts	F°	Ohms	Volts	F°	Ohms	Volts
1	82,719	2.94	21	44,879	2.70	41	25,391	2.37	61	14,921	1.97	81	9,076	1.57	101	5,697	1.19	121	3,679	0.88
2	80,142	2.94	22	43,577	2.69	42	24,704	2.35	62	14,543	1.95	82	8,861	1.55	102	5,570	1.18	122	3,602	0.87
3	77,656	2.92	23	42,318	2.67	43	24,037	2.33	63	14,176	1.93	83	8,651	1.53	103	5,446	1.16	123	3,527	0.86
4	75,255	2.91	24	41,099	2.65	44	23,391	2.31	64	13,820	1.91	84	8,447	1.51	104	5,326	1.15	124	3,454	0.84
5	72,937	2.90	25	39,919	2.64	45	22,764	2.29	65	13,473	1.89	85	8,249	1.49	105	5,208	1.13	125	3,382	0.83
6	70,698	2.89	26	38,777	2.62	46	22,156	2.28	66	13,136	1.87	86	8,056	1.47	106	5,094	1.12	126	3,312	0.82
7	68,535	2.88	27	37,671	2.61	47	21,566	2.26	67	12,809	1.85	87	7,867	1.45	107	4,982	1.10	127	3,244	0.81
8	66,447	2.87	28	36,601	2.59	48	20,993	2.24	68	12,491	1.83	88	7,684	1.43	108	4,873	1.08	128	3,177	0.80
9	64,428	2.86	29	35,565	2.57	49	20,438	2.22	69	12,182	1.82	89	7,506	1.41	109	4,767	1.06	129	3,112	0.79
10	62,479	2.84	30	34,561	2.56	50	19,900	2.20	70	11,882	1.80	90	7,333	1.40	110	4,664	1.05	130	3,049	0.77
11	60,595	2.83	31	33,590	2.54	51	19,377	2.18	71	11,589	1.77	91	7,164	1.38	111	4,563	1.04	131	2,987	0.76
12	58,774	2.82	32	32,648	2.53	52	18,870	2.16	72	11,305	1.75	92	6,999	1.36	112	4,464	1.02	132	2,926	0.75
13	57,014	2.81	33	31,737	2.51	53	18,377	2.14	73	11,029	1.73	93	6,839	1.34	113	4,368	1.00	133	2,867	0.73
14	55,313	2.79	34	30,853	2.49	54	17,899	2.12	74	10,761	1.71	94	6,683	1.32	114	4,274	0.99	134	2,809	0.73
15	53,669	2.78	35	29,998	2.48	55	17,435	2.10	75	10,500	1.69	95	6,530	1.31	115	4,183	0.97	135	2,752	0.71
16	52,078	2.77	36	29,169	2.46	56	16,985	2.08	76	10,246	1.67	96	6,382	1.29	116	4,094	0.96	136	2,697	0.70
17	50,541	2.75	37	28,365	2.44	57	16,548	2.06	77	9,999	1.65	97	6,238	1.27	117	4,007	0.94	137	2,643	0.69
18	49,054	2.74	38	27,587	2.42	58	16,123	2.04	78	9,758	1.63	98	6,097	1.25	118	3,922	0.93	138	2,591	0.68
19	47,616	2.73	39	26,832	2.40	59	15,711	2.02	79	9,525	1.61	99	5,960	1.23	119	3,839	0.92	139	2,539	0.67
20	46,225	2.71	40	26,100	2.38	60	15,310	1.99	80	9,297	1.59	100	5,827	1.21	120	3,758	0.90	140	2,489	0.66

 

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 2, 2025

• Add bookmark
• #33

Note: The first chart is for ProLogic and AquaLogic with a 5 volt DC temperature sensor.

The bottom chart is for a 3.3 volt DC water temperature sensor assuming a 10k ohm internal resistance for the ohmmeter.

I think that the bottom chart applies to OmniLogic, but I am not 100% sure.

 

D

davidl81

0

Oct 8, 2018

31

HUMBLE, TX

• Mar 5, 2025

• Add bookmark
• #34

So I did swap the solar and air sensor with no success. I also did a hot cup of water and the air sensor still just showed 78degs. Went ahead and called the service company. It was an issue with the main PCM board they he thinks was caused by a faulty power supply. They ended up replacing both and everything works fine now, except I’m broke because of the bill lol.

 

• 

Reactions: JamesW

J

JamesW

TFP Expert

Mar 2, 2011

51,596

• Mar 6, 2025

• Add bookmark
• #35

TFP is a registered 501(c)3 non-profit that is maintained by user donations.

All of our content is free of advertisements.

Please consider donating at:

Become a TFP Supporter

Help Support TFP Trouble Free Pool is run by a dedicated group of volunteers that … Read more…

www.troublefreepool.com